This allows creating tables in any target tablespace rather than the default
one, and is supported for the various sources having support for the ALTER
TABLE clause 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.