Remove the unused code from the manager

[Senyoret1]

Feature description
The Skywire manager has a lot of unused code that was left from the previous version and was not deleted just in case something was needed, as a lot of changes were still being made. However, as the manager is now more mature, the code should be deleted. If something is needed, the code is still in the testnet repo.

Is your feature request related to a problem? Please describe.
The unused code makes the UI code much more difficult to underestand and maintain.

Describe the solution you'd like
All unused components should be removed, all related translation strings deleted and the styles removed. After that, the style files can be restructured in a simpler way.