refactor(backend): switch to empty buildpack for package, extend supported OS versions (#10705) (#10712)

* bump vers

* fix ssl?

Added build dependencies for libbz2, libffi, and libssl.

* try empty buildpack

* clean up

* fix ref

* remove things we now do not need anymore

* add 22.04 as a target

* cleanup installer

* add changelog entry

* add dotenv

* update skript

* make task more robust for package usage

* ensure we have a site-url set

* fix style

* fix syntax

(cherry picked from commit f47a1a4675)

.pkgr.yml

@@ -2,10 +2,8 @@ name: inventree
 description: Open Source Inventory Management System
 homepage: https://inventree.org
 notifications: true
-buildpack: https://github.com/mjmair/heroku-buildpack-python#v216-mjmair
+buildpack: https://github.com/matmair/null-buildpack#master
 env:
-  - STACK=heroku-20
-  - DISABLE_COLLECTSTATIC=1
   - INVENTREE_DB_ENGINE=sqlite3
   - INVENTREE_DB_NAME=database.sqlite3
   - INVENTREE_PLUGINS_ENABLED
@@ -38,4 +36,7 @@ dependencies:
   - "libffi7 | libffi8"
 targets:
   ubuntu-20.04: true
+  ubuntu-22.04: true
+  ubuntu-24.04: true
   debian-11: true
+  debian-12: true