Build scripts for new releng
For most builds, this does not add any extra functionality, but many of
the builds now have a structure where changes to the releng script alone
can be used to improve the behavior.
Convert earlier bash scripts for documentation and uncrustify builds
to Python with similar functionality. The old scripts are there for now
to make it possible to merge this while still keeping the old builds
fully functional.
Also, make uncrustify.sh --warnings= flag work properly with absolute
path names to make it easier to use in the new script.
Change-Id: I23ad807183e2d9b5b03f0a5c1bd2b9f5cd6992fc