[Documentation] Update visuals for user guide and fix typos

[bruhnild]

No description provided.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 94.99%. Comparing base (b069004) to head (34ad23c).
Report is 10 commits behind head on master.

❗ Current head 34ad23c differs from pull request most recent head a714447. Consider uploading reports for the commit a714447 to get more accurate results

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #570   +/-   ##
=======================================
  Coverage   94.99%   94.99%           
=======================================
  Files          81       81           
  Lines        2975     2975           
=======================================
  Hits         2826     2826           
  Misses        149      149           

Flag	Coverage Δ
backend-unittests	94.99% <ø> (ø)

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[bruhnild]

https://terravisu.readthedocs.io/en/mfu-improve-documentation/user_manual/user_guide.html