RFC: use semodule --checksum and priorities instead of datastore

I probably miss some piece of the puzzle but it looks like all datastore functionality could be implemented using `semodule` utility or *libsemanage* library. Bellow are shell snippets describing how it could work.

* List()
`semodule -lfull | grep -E '^350 `

* Put() is not necessagy, it's automatically covered by `semodule -i ...`

* Get()
~~~
# semodule -lfull --checksum | grep -E '^350 ' | grep $policy
350 testpolicy cil sha256:0d682da9f705d4a44bad5151c59598f96a1839e10efe5f00b2bd16ba3c562676
~~~

This works on Fedora 36, RHEL-8.6, and RHEL9 and later

* Remove() - automatically covered by `semodule -r ...`

Start by tracing the existing datastore implementation and compare its List, Get, Put, and Remove behavior with the semodule commands and libsemanage mentioned in the issue. Check the stated Fedora and RHEL versions; done means reaching agreement on the replacement design and its compatibility and behavior.

Written by the indexing model from the issue text.