Add Doxygen functionality on Linux GitHub Workflow

[MichaelBCG]

This pull request adds functionality for generating code documentation with Doxygen and publishing it on GitHub Pages using Linux GitHub Workflows.

To utilize this feature, you'll need to specify branches in the doxygen-linux.yml file.

There are a couple of peculiarities when running Doxygen on Linux that I've addressed:

• Paths in Doxygen configuration file (Doxyfile) must be specified using forward slashes, whereas they're originally represented with backslashes. To handle this, I've included the replace-path-backslashes.py script, which is executed within a Linux GitHub Workflow to convert backslashes to forward slashes.
• By default, Python scripts cannot be called using the py command on Linux GitHub-hosted virtual machines. This poses an issue because the py command is utilized within the Doxyfile, such as INPUT_FILTER tag. To resolve this, a symbolic link is created during the Linux GitHub Workflow.

I've tested this functionality on my repository. Please review and merge it if appropriate.

[MichaelBCG]

## This comment illustrates how the script works.
## Below are the pairs of lines. The first line (which is commented) in each pair is an original line with back slashes "\". It was not be affected by the script
## The second line (which is not commented) in each pair is the result illustrating how the script processed the line above it

#\ \asdf \asdf\ asdf\ asdf\asdf \
\ /asdf /asdf/ asdf/ asdf/asdf \

# \ \asdf \asdf\ asdf\ asdf\asdf \
 \ /asdf /asdf/ asdf/ asdf/asdf \

#\asdf \asdf\ asdf\ asdf\asdf
/asdf /asdf/ asdf/ asdf/asdf

#\asdf \asdf\ asdf\ asdf\asdf\
/asdf /asdf/ asdf/ asdf/asdf/

#\asdf \asdf\ asdf\ asdf \asdf
/asdf /asdf/ asdf/ asdf /asdf

#\asdf \asdf\ asdf\ asdf \asdf\
/asdf /asdf/ asdf/ asdf /asdf/

# \" \asdf \asdf\" asdf\ asdf\asdf \
 \" /asdf /asdf\" asdf/ asdf/asdf \

#\" \asdf \asdf\" asdf\ asdf\asdf \
\" /asdf /asdf\" asdf/ asdf/asdf \

# HTML_FOOTER            = devops\docs\doxygen-dark-theme\html_footer.html
HTML_FOOTER            = devops/docs/doxygen-dark-theme/html_footer.html

# HTML_EXTRA_FILES       = devops\docs\doxygen_theme_flat_design\src\img\closed-folder.png \
# devops\docs\doxygen_theme_flat_design\src\img\opened-folder.png
HTML_EXTRA_FILES       = devops/docs/doxygen_theme_flat_design/src/img/closed-folder.png \
devops/docs/doxygen_theme_flat_design/src/img/opened-folder.png