Replace docs build-site.py with default-ish sphinx build
This seems to speed up docsite build _alot_.
The Makefile.sphinx is the sphinx-quickstart generated makefile with a few changes.
The CPUS env var or 'nproc' output is used for the number of cpus passed to 'sphinx-build -j'
Because we add the names of all filters to the callable whitelist used
by safe_eval, adding a filter named type makes it so code calling "type()"
gets eval'd. We can't think of a way to exploit this but it's
sufficiently sketchy that we're renaming it in case someone smarter than
us can think of a problem.
Instead of asking the user to type something prior to running the script, why not allow -Verbose on the command line directly.
Also log important events to EventLog, so that it can be traced e.g. when running via RunOnce mechanism.
The documentation is updated as well.
* developing_modules.rst is now in dev_guide, sync changes and delete the old version
* Cleaner RST & formatted code
* Tidyup roadmaps
* Link to repomerge
* Pull in abadger's fixes From https://github.com/ansible/ansible/compare/docs-code-block-fixes?expand=1
* Clean docsite/rst (apart from ROADMAP
