More matrix_postgres -> devture_postgres changes

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/2319

docs/maintenance-postgres.md

@@ -99,7 +99,7 @@ Example: `--extra-vars="postgres_dump_name=matrix-postgres-dump.sql"`
 
 ## Tuning PostgreSQL
 
-PostgreSQL can be tuned to make it run faster. This is done by passing extra arguments to Postgres with the `matrix_postgres_process_extra_arguments` variable. You should use a website like https://pgtune.leopard.in.ua/ or information from https://wiki.postgresql.org/wiki/Tuning_Your_PostgreSQL_Server to determine what Postgres settings you should change.
+PostgreSQL can be tuned to make it run faster. This is done by passing extra arguments to Postgres with the `devture_postgres_process_extra_arguments` variable. You should use a website like https://pgtune.leopard.in.ua/ or information from https://wiki.postgresql.org/wiki/Tuning_Your_PostgreSQL_Server to determine what Postgres settings you should change.
 
 **Note**: the configuration generator at https://pgtune.leopard.in.ua/ adds spaces around the `=` sign, which is invalid. You'll need to remove it manually (`max_connections = 300` -> `max_connections=300`)
 
@@ -109,7 +109,7 @@ These are not recommended values and they may not work well for you. This is jus
 
 Here is an example config for a small 2 core server with 4GB of RAM and SSD storage:
 ```
-matrix_postgres_process_extra_arguments: [
+devture_postgres_process_extra_arguments: [
   "-c shared_buffers=128MB",
   "-c effective_cache_size=2304MB",
   "-c effective_io_concurrency=100",
@@ -120,7 +120,7 @@ matrix_postgres_process_extra_arguments: [
 
 Here is an example config for a 4 core server with 8GB of RAM on a Virtual Private Server (VPS); the paramters have been configured using https://pgtune.leopard.in.ua with the following setup: PostgreSQL version 12, OS Type: Linux, DB Type: Mixed type of application, Data Storage: SSD storage:
 ```
-matrix_postgres_process_extra_arguments: [
+devture_postgres_process_extra_arguments: [
   "-c max_connections=100",
   "-c shared_buffers=2GB",
   "-c effective_cache_size=6GB",
@@ -142,7 +142,7 @@ matrix_postgres_process_extra_arguments: [
 
 Here is an example config for a large 6 core server with 24GB of RAM:
 ```
-matrix_postgres_process_extra_arguments: [
+devture_postgres_process_extra_arguments: [
   "-c max_connections=40",
   "-c shared_buffers=1536MB",
   "-c checkpoint_completion_target=0.7",