build: subpackages implementation (#164)

* migrate to hatch

* reorder tests

* generic fixtures

* straight forward conftest

* fix docs generation

* fix tox environments

* reformat tomls

* cleanup pyproject

* some play with renaming

* move root conftest into pytest plugins

* fix setup script

* move fixtures to __init__.py

* remove duplicate fixtures

* disable pylint warning

* simplify configuration fixture

* remove empty conftest

* remove crap from local pyprojects

ahriman-core/package/lib/systemd/system/ahriman@.service

@@ -0,0 +1,7 @@
+[Unit]
+Description=ArcH linux ReposItory MANager (%i)
+
+[Service]
+ExecStart=/usr/bin/ahriman --repository-id "%I" repo-update --refresh
+User=ahriman
+Group=ahriman