Make detekt plugin opt-in per-project

[rock3r]

On projects that already have detekt enabled, this makes no difference. For projects that don't have detekt enabled, the plugin will ask on project open to enable it or opt out for the current project. Users can always use the IDE settings to turn on detekt as before.

The detekt configuration UI has also been overhauled, by reorganizing settings in a more intuitive way. The main on/off switch for detekt analysis has been placed prominently at the top of the configuration page, and the tooltip has been turned into a comment for easier understanding, as its wording is a tad cryptic. The "common options" section is now "plugin options" — as those relate to the IDE plugin rather than detekt proper.

The implicit dependency of the debug mode on the stdout/stderr redirect has been made explicit with an indent, and a UI DSL bug worked around where custom components wouldn't get properly disabled by enabledIf bindings.

Darcula	New UI Dark

This PR closes #479

[rock3r]

@arturbosch any feedback?

[arturbosch]

@arturbosch any feedback?

Looks good to me!

Can we implement DumpAware or something here?

Should we rename this <option name="optIn" value="OptedIn" />? After a week the user forgot what OptedIn means and ask if we collect telemetry or something. Maybe even Jetbrains Marketplace will ask what it means ^_^. EnableDialogShowedOnFirstRun with true|false ?

[rock3r]

@arturbosch all addressed :)