When we released Review Bot 1.0, it was important that we included

information on migrating from Review Bot 0.1/0.2 to 1.0. This is

probably less important today, but certainly the old information

referenced the 1.0 version too heavily and didn't really aid in

upgrading from 1.0 to 2.0.
This change rewrites the installation docs to focus more on generation

installation, cleaning up some parts in the process to reflect how

things work now.
The upgrade information has been split into a new page, which we may add

to down the road if the process changes. There's details on upgrading

both from Review Bot 1.0+, and from the old 0.1/0.2 releases.
The version number of the documentation is now based on the extension

version, instead of hard-coding "1.0".
Some of the new features/tools have been marked with a "added in 2.0"

note, to help make clear what's new.
There's also a fix for the doc8 instructions, which mistakenly

referred to pydocstyle.

Built the docs. Checked for bad links and spelling/build errors.