Fix some minor issues found by sonarqube

[maxnoe]

• Use https where possible
• Use NamedTemporaryFile instead of mktemp

[codecov]

Codecov Report

Attention: 2 lines in your changes are missing coverage. Please review.

Comparison is base (c05b493) 92.47% compared to head (30fd288) 92.47%.
Report is 2 commits behind head on main.

Files	Patch %	Lines
ctapipe/visualization/bokeh.py	33.33%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2466      +/-   ##
==========================================
- Coverage   92.47%   92.47%   -0.01%     
==========================================
  Files         234      234              
  Lines       19816    19817       +1     
==========================================
  Hits        18325    18325              
- Misses       1491     1492       +1     

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