Updated the introduction and state of the art.

Added a new chapter which will include a detailed overview on how SPA works.
This section might do better as an appendix in the future.
Updated the state of the art for SPA.
Removed some spaces in the reference file.
Added comment about future research when it comes to MTU and routing.
Updated the introduction.
Moved some parts about SPA from State of the Art to its own chapter.
Changed structure in the method chapter and added a note in the SPA chapter.
Changed Avionics to Architecture throughout the report.
Merge branch 'feature/notes_about_references' into development
Merge branch 'development' into feature/report
Added some text on how the literature study was conducted.
Added some more ideas for future research.
Merge branch 'feature/notes_about_references' into development
Merge branch 'development' into feature/report
Started on the SOTA for SPA.
Merge branch 'feature/notes_about_references' into development
Merge branch 'development' into feature/report
Updated state of the art and added a reference.
Merge branch 'feature/report' into development
Merge branch 'development' into feature/notes_about_references