That helps having both an overview of what pgloader is capable of doing with
a database migration, and also documenting that some sources don't have the
full support for some features yet.
We have a lot of new features to document. This is a first patch about that,
some more work is to be done. That said, it's better than nothing already.
The website is moving to pgloader.org and readthedocs.io is going to be
integrated. Let's see what happens. The docs build fine locally with the
sphinx tools and the docs/Makefile.
Having separate files for the documentation should help ease the maintenance
and add new topics, such as support for Common Lisp Hackers level docs,
which are currently missing.
