Move command manager to its own project

[MeikelLP]

discovered the need in #125

Command manager and implemented commands are mixed in several projects and directories.

To clean this up I did:

• Libraries/Game.Commands - CommandManager and related files
• Tests/Game.Commands.Tests - Only tests the command manager and related files. The CommandTests still exists in the Game.Tests because it tests implemented tests not the command manager
• Moved CommandManager and related files to QuantumCore.Game.Commands namespace
• Moved some service interfaces like IJobManager and IExperienceManager to CorePluginAPI (bonus - not required)
• Added StrictMode (via options) to CommandManager which causes it to throw a CommandHandlerNotFoundException if a command handler cannot be found. This is by default false but is on in tests to help debug if some code is not executed by default.

[sonarcloud[bot]]

Quality Gate failed

Failed conditions
C Reliability Rating on New Code (required ≥ A)

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