various doc updates in prep for 0.23 (#2091)

* various doc updates in prep for 0.23

Signed-off-by: Kristoffer Dalby <kristoffer@tailscale.com>

* add note discouraging postgresql

Signed-off-by: Kristoffer Dalby <kristoffer@tailscale.com>

* Update docs/faq.md

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

* remove entry for glossary in doc

Signed-off-by: Kristoffer Dalby <kristoffer@tailscale.com>

* fix typo

Signed-off-by: Kristoffer Dalby <kristoffer@tailscale.com>

---------

Signed-off-by: Kristoffer Dalby <kristoffer@tailscale.com>
Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

config-example.yaml

@@ -138,6 +138,9 @@ disable_check_updates: false
 ephemeral_node_inactivity_timeout: 30m
 
 database:
+  # Database type. Available options: sqlite, postgres
+  # Please not that using Postgres is highly discouraged as it is only supported for legacy reasons.
+  # All new development, testing and optimisations are done with SQLite in mind.
   type: sqlite
 
   # Enable debug mode. This setting requires the log.level to be set to "debug" or "trace".
@@ -166,6 +169,8 @@ database:
     write_ahead_log: true
 
   # # Postgres config
+  # Please note that using Postgres is highly discouraged as it is only supported for legacy reasons.
+  # See database.type for more information.
   # postgres:
   #   # If using a Unix socket to connect to Postgres, set the socket path in the 'host' field and leave 'port' blank.
   #   host: localhost