[Added] Plugin Configuration UI is completed.
Plugins can be connected and loaded and unloaded using the UI.

[FIXED] _api within the NoobaPlugin is connected through signal slots
for the parameter updates received from the main thread to make the
signals and slots run in different threads.

[CHANGED] signals emitted on release and unload are changed to pass the
alias of the plugin rather than the pointer. When the signal is received from
a different thread plugin is already deleted, in most times.