Support Gradle files from plugins and merge android resource files using aapt

[Fatme]

Plugin structure

• All resource files (AndroidManifest.xml, strings.xml, styles.xml) should be inside platforms/android folder in plugin. The manifest should be in the root and all other resources should be in the respective folders (res\...)
• The user should be able to create include.gradle file in platforms/android folder. If the plugin doesn't contain include.gradle CLI will generate a default one.

Plugin Prepare command

CLI will copy the include.gradle file from the plugin if such file exists to platforms/android/src/plugins/<plugin-name> directory. In case where such files does not exist a default one will be generated.

CLI will create platforms/android/src/plugins/<plugin-name> directory and will copy all resource files from plugin to this folder. They will be automatically merged by the aapt tool.

Plugin remove command

CLI will remove platforms/android/src/plugins/<plugin-name> and platforms/android/src/<plugin-name> directories