added a customizable plugin system

- the base LUA functionality has been implemented as a mandatory plugin
- the jtacautolase functionality has been implemented as a plugin
- added a VEAF framework plugin

The plugins have GUI elements in the Settings window.

plugin/liberation_plugin.py

@@ -0,0 +1,20 @@
+from .base_plugin import BasePlugin
+
+class LiberationPlugin(BasePlugin):
+    nameInUI:str = "Liberation script"
+    nameInSettings:str = "plugin.liberation"
+    enabledDefaultValue:bool = True
+
+    def setupUI(self, settingsWindow, row:int):
+        # Don't setup any UI, this plugin is mandatory
+        pass
+    
+    def injectScripts(self, operation):
+        if super().injectScripts(operation):
+            operation.injectPluginScript("base", "mist_4_3_74.lua", "mist")
+            operation.injectPluginScript("base", "json.lua", "json")
+            operation.injectPluginScript("base", "dcs_liberation.lua", "liberation")
+
+    def injectConfiguration(self, operation):
+        if super().injectConfiguration(operation):
+            pass