[Feature] - Colour file icons of config-files according to usage in an agent config

[MariusBrill]

Is your feature request related to a problem? Please describe.
Currently, all file icons in the file tree are coloured grey. As a user i would find it helpful if this colour would be used to indicate if a config is currently used in an active agent config or not. It would help to better understand to which degree files are actively used. Also it helps prevent user errors - for instance when a user edits a file that is not actively used in the agent config.

Describe the solution you'd like
These icons should be displayed in grey when not used in an agent configuration and another color, eg green or the inspectIT-orange when used in an agent configuration.