Move config task docs to a separate file and mark it as WIP

docs/administration/CLI_tasks/config.md

@@ -0,0 +1,19 @@
+# Transfering the config to/from the database
+
+!!! danger
+    This is a Work In Progress, not usable just yet.
+
+Every command should be ran with a prefix, in case of OTP releases it is `./bin/pleroma_ctl config` and in case of source installs it's
+`mix pleroma.config`.
+
+## Transfer config from file to DB.
+
+```sh
+$PREFIX migrate_to_db
+```
+
+## Transfer config from DB to `config/env.exported_from_db.secret.exs`
+
+```sh
+$PREFIX migrate_from_db <env>
+```