Decouple settings logic

[frextrite]

Currently, we have 3 classes for working with settings

• ProjectSettings (a ProjectComponent) handles the runtime settings (if any)
• CodeAnalysisSettingsPage contains logic for settings page
• CodeAnalysisSettingsPersistent to persist the settings to the fs

Changes done in settings page, need to modify both the other classes.

Possible solution:

• Make CodeAnalysisSettingsPage an applicationConfigurable and CodeAnalysisSettingsPersistent as an ApplicationService
• the main action to run coala, would first call internal method to update ProjectSettings which would in-turn load all the settings from the persistent class and,
• all the other classes (in a particular project) would communicate directly with ProjectSettings class.