Move database maintenance tasks docs to a separate file

docs/administration/CLI_tasks/database.md

@@ -0,0 +1,48 @@
+# Database maintenance tasks
+
+Every command should be ran with a prefix, in case of OTP releases it is `./bin/pleroma_ctl database` and in case of source installs it's `mix pleroma.database`.
+
+## Replace embedded objects with their references
+
+Replaces embedded objects with references to them in the `objects` table. Only needs to be ran once if the instance was created before Pleroma 1.0.5. The reason why this is not a migration is because it could significantly increase the database size after being ran, however after this `VACUUM FULL` will be able to reclaim about 20% (really depends on what is in the database, your mileage may vary) of the db size before the migration.
+
+```sh
+$PREFIX remove_embedded_objects [<options>]
+```
+
+### Options
+- `--vacuum` - run `VACUUM FULL` after the embedded objects are replaced with their references
+
+## Prune old remote posts from the database
+
+This will prune remote posts older than 90 days (configurable with [`config :pleroma, :instance, remote_post_retention_days`](../../configuration/cheatsheet.md#instance)) from the database, they will be refetched from source when accessed.
+
+!!! note
+    The disk space will only be reclaimed after `VACUUM FULL`
+
+```sh
+$PREFIX pleroma.database prune_objects [<options>]
+```
+
+### Options
+- `--vacuum` - run `VACUUM FULL` after the objects are pruned
+
+## Create a conversation for all existing DMs
+
+Can be safely re-run
+
+```sh
+$PREFIX bump_all_conversations
+```
+
+## Remove duplicated items from following and update followers count for all users
+
+```sh
+$PREFIX update_users_following_followers_counts
+```
+
+## Fix the pre-existing "likes" collections for all objects
+
+```sh
+$PREFIX fix_likes_collections
+```

lib/mix/tasks/pleroma/database.ex

@@ -13,34 +13,7 @@ defmodule Mix.Tasks.Pleroma.Database do
   use Mix.Task
 
   @shortdoc "A collection of database related tasks"
-  @moduledoc """
-   A collection of database related tasks
 
-   ## Replace embedded objects with their references
-
-   Replaces embedded objects with references to them in the `objects` table. Only needs to be ran once. The reason why this is not a migration is because it could significantly increase the database size after being ran, however after this `VACUUM FULL` will be able to reclaim about 20% (really depends on what is in the database, your mileage may vary) of the db size before the migration.
-
-       mix pleroma.database remove_embedded_objects
-
-    Options:
-    - `--vacuum` - run `VACUUM FULL` after the embedded objects are replaced with their references
-
-  ## Prune old objects from the database
-
-      mix pleroma.database prune_objects
-
-  ## Create a conversation for all existing DMs. Can be safely re-run.
-
-      mix pleroma.database bump_all_conversations
-
-  ## Remove duplicated items from following and update followers count for all users
-
-      mix pleroma.database update_users_following_followers_counts
-
-  ## Fix the pre-existing "likes" collections for all objects
-
-      mix pleroma.database fix_likes_collections
-  """
   def run(["remove_embedded_objects" | args]) do
     {options, [], []} =
       OptionParser.parse(