feat: support Git LFS on plain gitea

Add an opt-in compose.lfs.yml that mounts the lfs_jwt_secret secret and
enables GITEA_LFS_START_SERVER for plain gitea (forgejo already bundles
LFS). Emit LFS_JWT_SECRET in app.ini whenever the LFS server is on so the
JWT secret is stable across redeploys instead of being regenerated on
every restart (app.ini is a read-only config mount).

Bump version 3.5.2 -> 3.6.0.

abra.sh

@@ -1,4 +1,4 @@
-export APP_INI_VERSION=v22
+export APP_INI_VERSION=v21
 export DOCKER_SETUP_SH_VERSION=v1
 export PG_BACKUP_VERSION=v1
 

compose.postgres.yml

@@ -10,7 +10,7 @@ services:
     secrets:
       - db_password
   db:
-    image: postgres:15.18
+    image: postgres:15.13
     deploy:
       labels:
         backupbot.backup.pre-hook: "/pg_backup.sh backup"

compose.yml

@@ -3,7 +3,7 @@ version: "3.8"
 
 services:
   app:
-    image: "gitea/gitea:1.26.2-rootless"
+    image: "gitea/gitea:1.24.2-rootless"
     configs:
       - source: app_ini
         target: /etc/gitea/app.ini