Creating generic mautrix bridge doc (#1912)

* Creating generic mautrix bridge doc

Not a huge fan of how it turned out at all, not sure how to make it better.

* Rename configuring-playbook-bridge-mautrix-Generic.md to configuring-playbook-bridges.md

* accepting suggested edits after rename mess

* Adding log level configuration

* Update docs/configuring-playbook-bridges.md

Co-authored-by: Slavi Pantaleev <slavi@devture.com>

* Rename configuring-playbook-bridges.md to configuring-playbook-mautrix-bridges.md

Co-authored-by: ThellraAK <ThellraAK@pop-os.localdomain>
Co-authored-by: Slavi Pantaleev <slavi@devture.com>

docs/configuring-playbook-mautrix-bridges.md

@@ -0,0 +1,111 @@
+# Setting up a Generic Mautrix Bridge (optional)
+
+The playbook can install and configure various [mautrix](https://github.com/mautrix) bridges (twitter, facebook, instagram, signal, hangouts, googlechat, etc.), as well as many other (non-mautrix) bridges.
+This is a common guide for configuring mautrix bridges.
+
+You can see each bridge's features at in the `ROADMAP.md` file in its corresponding [mautrix](https://github.com/mautrix) repository.
+
+To enable a bridge add:
+
+
+```yaml
+# Replace SERVICENAME with one of: twitter, facebook, instagram, ..
+matrix_mautrix_SERVICENAME_enabled: true
+```
+
+to your `vars.yml`
+
+There are some additional things you may wish to configure about the bridge before you continue. Each bridge may have additional requirements besides `_enabled: true`. For example, the mautrix-telegram bridge (our documentation page about it is [here](configuring-playbook-bridge-mautrix-telegram.md)) requires the `matrix_mautrix_telegram_api_id` and `matrix_mautrix_telegram_api_hash` variables to be defined. Refer to each bridge's individual documentation page for details about enabling bridges.
+
+You can add
+
+```yaml
+matrix_admin: "@YOUR_USERNAME:{{ matrix_domain }}"
+```
+to `vars.yml` to **configure a user as an administrator for all bridges**.
+**Alternatively** (more verbose, but allows multiple admins to be configured), you can do the same on a per-bridge basis with:
+
+```yaml
+matrix_mautrix_SERVICENAME_configuration_extension_yaml: |
+  bridge:
+    permissions:
+      '@YOUR_USERNAME:{{ matrix_domain }}': admin
+```
+
+Encryption support is off by default. If you would like to enable encryption, add the following to your `vars.yml` file:
+```yaml
+matrix_mautrix_SERVICENAME_configuration_extension_yaml: |
+  bridge:
+    encryption:
+      allow: true
+      default: true
+```
+
+
+You can only have one `matrix_mautrix_SERVICENAME_configuration_extension_yaml` definition in `vars.yml` per bridge, so if you need multiple pieces of configuration there, just merge them like this:
+
+```yaml
+matrix_mautrix_SERVICENAME_configuration_extension_yaml: |
+  bridge:
+    permissions:
+      '@YOUR_USERNAME:{{ matrix_domain }}': admin
+    encryption:
+      allow: true
+      default: true
+```
+
+## Setting the bot's username
+
+```yaml
+matrix_mautrix_SERVICENAME_appservice_bot_username: "BOTNAME"
+```
+
+Can be used to set the username for the bridge.
+
+## Discovering additional configuration options
+
+You may wish to look at `roles/matrix-bridge-mautrix-SERVICENAME/templates/config.yaml.j2` and `roles/matrix-bridge-mautrix-SERVICENAME/defaults/main.yml` to find other things you would like to configure.
+
+
+## Set up Double Puppeting
+
+To set up  [Double Puppeting](https://docs.mau.fi/bridges/general/double-puppeting.html)
+
+please do so automatically, by enabling Shared Secret Auth
+
+The bridge will automatically perform Double Puppeting if you enable [Shared Secret Auth](configuring-playbook-shared-secret-auth.md) for this playbook by adding
+
+```yaml
+matrix_synapse_ext_password_provider_shared_secret_auth_enabled: true
+matrix_synapse_ext_password_provider_shared_secret_auth_shared_secret: YOUR_SHARED_SECRET_GOES_HERE
+```
+
+You should generate a strong shared secret with a command like this: pwgen -s 64 1
+
+This is the recommended way of setting up Double Puppeting, as it's easier to accomplish, works for all your users automatically, and has less of a chance of breaking in the future.
+
+## Controlling the logging level
+
+```yaml
+matrix_mautrix_SERVICENAME_logging_level: WARN
+```
+
+to `vars.yml` to control the logging level, where you may replace WARN with one of the following to control the verbosity of the logs generated:     TRACE, DEBUG, INFO, WARN, ERROR, or FATAL.
+
+If you have issues with a service, and are requesting support, the higher levels of logging will generally be more helpful.
+
+
+## Usage
+
+You then need to start a chat with `@SERVICENAMEbot:YOUR_DOMAIN` (where `YOUR_DOMAIN` is your base domain, not the `matrix.` domain). 
+
+Send `login ` to the bridge bot to get started You can learn more here about authentication from the bridge's official documentation on Authentication https://docs.mau.fi/bridges/python/SERVICENAME/authentication.html  .
+
+If you run into trouble, check the [Troubleshooting](#troubleshooting) section below.
+
+
+
+## Troubleshooting
+
+For troubleshooting information with a specific bridge, please see the playbook documentation about it (some other document in in `docs/`) and the upstream ([mautrix](https://github.com/mautrix)) bridge documentation for that specific bridge.
+Reporting bridge bugs should happen upstream, in the corresponding mautrix repository, not to us.