Draft: gst-indent: build our own indent tool and make it available in the devenv

No more formatting mismatches owing to different GNU indent versions shipped by different distro versions.

#340 (closed)

Todo

• Needs to go over the input twice in order to produce a stable result (blocker, same as gst-indent script does now)
• Should maintain CRLF line endings in source files with CRLF (not a blocker, but important for Windows)
• What to do with gst-indent-all? (not a blocker, only used on CI?)
• Move gst-indent job over to new tool (can be done in a separate step later)
• General approach
  • This MR builds our gst-indent as part of the regular meson configure/build, which means the binary will only be available once a build has completed.
  • An alternative approach could be something like checking out the gst-indent project as git submodule (which could be done automatically on git clone of the monorepo I think), and then our wrapper script could build it on-demand on first use. Which means that build would be independent of the main monorepo build, but I'm not sure if that's really worth it or necessary, not sure if it solves any actual problem.
• Update gst-docs/markdown/contribute/index.md
• Update gst-docs/markdown/frequently-asked-questions/developing.md
• Update gst-plugins-{base,good,bad}/scripts/update-orc-dist-files.py
• Update gst-plugins-bad/tools/gst-*-maker scripts