Add hierarchy commitee sort

[bastianjoel]

resolves #5325

[MSoeb]

In general: The committee hierachy view should be improved in several ways, which will be done in small steps. Topic was discussed with Bastian, Emanuel, Martin and me.

What should be changed now:

• Just like in a file explorer lines and triangles should be placed in front of the committee names to made the relations visible more clear.
• Triangles Root level: triangle should be open at top
• Triangle for sub levels: triangles should be open to the left side

here an example, how it should look:

Further information what comes next:

• Fold in/ fold out for committees with sub levels / please do research about this.
• How to handle search in hierarchy view
• possible new view in a folder stlye

[luisa-beerboom]

Code currently looks good

[luisa-beerboom]

Fix linting though

[bastianjoel]

@MSoeb what is missing here?

[MSoeb]

The collapsing structure didn't work properly.

First issue

Folder 4.2.19 - closed

Folder opened

---> Two problems appear. The folder has two sub committees. One is not displayed. Second issue, the sub folder opens at the wrong point. It should open right beneath the main folder. (Kind belongs to 4.2.19.) - I think this issue occurs with existing committees. But not with all of them. Don't know how and why it happens. - I think it would be good, if I show it.

Second Issue:
The layout of the sub level committee tree is not correct. If there are no more sub levels, the lines to the folder should end with a 90-degree angle.

Example - Kind committee. The line to down is wrong.

Third issue:
In sub level folders a triangle should be displayed. Just like in the mock-up.