Locks conan to 1.59 for GUI builds

[martukas]

Description

updates #1324

As described in ticket above, there is a new syntax for the recently released conan 2.0, but not all the tooling has yet adapted to it. We will skip adopting it until cmake gets its act together. This patch temporarily fixes the problem.

bonus: had to update some of the images related to software architecture docs as link checker was failing.

Self-review checklist:

• Self-review: looked through the Files changed tab, browsed repository in branch
• Documentation updated - reflects changes in code, electrical or mechanical design
• Documentation and graphics follow the documentation style guide
• New content is linked, easily discoverable, does not require too many clicks
• Follows other relevant parts of contributor wiki
• PR has a descriptive name
• Tagged relevant reviewers

Software only:

• Follows our code style
• Commented code, particularly in hard-to-understand areas
• All tests pass - new and old, locally and on CI
• No new warnings or static check failures
• Tests that prove fix is effective or new feature works
• Manual tests are explained, with instructions for reproducing them

[codecov]

Codecov Report

Merging #1325 (a3f5048) into master (174fb66) will not change coverage.
The diff coverage is n/a.

❗ Current head a3f5048 differs from pull request most recent head 14443b1. Consider uploading reports for the commit 14443b1 to get more accurate results

@@           Coverage Diff           @@
##           master    #1325   +/-   ##
=======================================
  Coverage   57.20%   57.20%           
=======================================
  Files         104      104           
  Lines        3491     3491           
  Branches      321      321           
=======================================
  Hits         1997     1997           
  Misses       1494     1494           

Flag	Coverage Δ
common	95.90% <ø> (ø)
controller	57.37% <ø> (ø)
gui	28.17% <ø> (ø)

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[a-vinod]

LGTM