Ability for user specific IDE configuration

[hohwille]

As a IDEasy user, I want to be able to configure personal IDE settings so that I can automate my personal bells & whistles without repeating that manually for every project and every workspace.

This is already support (as an IMHO undocumented feature) for plugins:
Therefore I can create a folder ~/.ide/settings/ and in there I can add things like ~/.ide/settings/intellij/plugins/my-cool-plugin.properties in order to get my-cool-plugin into every IntelliJ installation of all my projects independent of the plugins configured for each of these projects via settings git repo.

Now it would be nice to have the same also for workspace configuration.
A very common use-case is to put the ultimate license into such central place avoiding to register IntelliJ ultimate for every project and every workspace.

Since we already support ~/.ide/ configuration folder conceptionally it would be more than natural to also allow that I can put my license into ~/.ide/intellij/workspace/setup/.intellij/config/idea.key and have the problem solved once and forever (until the license expires).
A lot of other such use-cases would be allowed this way.
However, with great flexibility comes some responsibility so users of such feature will have to know exactly what they are doing.
If they accidentally override project specific configuration, they can easily mess up everything.

Another level of flexibility would be to support the same also for $IDE_HOME/conf/settings/«ide»/workspace/.
By aligning the behaviour with the existing configuration order, things would be quite consistent.
So the project settings would still override things from the users home configuration while the settings from config again could override everything.

The implementation is very simple if done like with PR #731.