Move environment definition UI and color module dependency from environment_indicator to environment_indicator_ui

Problem/Motivation

environment_indicator currently requires to enable the color module. When using environment_indicator without UI (for example in Live Environments) you have to enable the color module only because environment_indicator has a dependency on it. This shouldn't be needed and affects performance (even if not much).

So I suggest moving the dependency from environment_indicator into environment_indicator_ui?

This frees us from the color module and makes the module more lightweight.

As result, we'd also have to move the environment definition using the color picker to the _ui submodule and only show the configuration and values from the settings.php in the base module.

That way the simplei module could also be superseded.

Steps to reproduce

Enable environment_indicator in a basic Drupal installation
Be forced to enable color module even if you don't need to use the UI

Proposed resolution

Move color module dependency into environment_indicator_ui

Remaining tasks

User interface changes

API changes

Data model changes