Move away from plugin annotations to configuration

[vbmacher]

Java annotations are easy for use by plugin programmer, but it has also few disadvantages, like emuStudio must "search for" annotated classes at runtime. Having everything in plugin configuration file decreases plugin development comfort a bit, but adds many positive features, like:

• Ability to describe the plugin offline, including context requirements or availability.
• plugin meta-data will be available in computer editor, before emulator starts.
• emuStudio won't need to search for annotations anymore, every class can be specified directly.

Suggested format is either yaml, toml, or hocon. Currently emuStudio utilizes toml.