Theme from doxygen-awesome-css with custom modifications based on the
pipewire.org website to use the same type of blue, grey, etc.
doxygen-awesome-css is MIT licensed, see
https://github.com/jothepro/doxygen-awesome-css
Note that the order of the includes matters - that's how doxygen will sort
them. There is no specific structure other than the include order - one reason
why the headers are being changed. Without polluting the markdown files with
doxygen commands we cannot use \subpage, so all files convert to a regular
\page and are listed as flat hierarchy in the sidebar (and in Related Pages).
Changing the headers at least provides some visual grouping with comon
prefixes.
Keep all files as strings in an array so we can add them to the custom command
input list - this way meson will correctly rebuild documentation on changes.
