java-systemd Working in ability to enable and disable units

Introduced a Struct and Pair class as needed by dbus-java
Updated various versions

I am labeling this version as 2.2.0-eks so if this commit is accepted, be sure to remove -eks.

FYI - For now, I needed to remove the -SNAPSHOT versioning since I will need to use this version in my system.

In a working state. Needed to also use a special struct class for the disableUnitFiles call (+3 squashed commit)

Squashed commit:

[9dde539] Found that enableUnitFiles may perform what I need to get units started.

The List<UnitFileChange> is not the proper return type. Some research lead me to AgNO3 project that uses a Tuple type of structure to hold the return type: https://github.com/AgNO3/code/blob/main/orchestrator/agent/system/eu.agno3.orchestrator.system.init.systemd/src/main/java/org/freedesktop/systemd1/Manager.java

Still experimenting...

[7197b50] WIP: TDD and fleshing out unit creation with dbus

[fb4e92d] Starting work towards creating/update/delete units

Specifically service units for now.
Using my own version number
Using lombok to reduce builder code. https://github.com/thjomnx/java-systemd/issues/6#issuecomment-1068341958