Move from a long list of checkers to tables

Summary:
Currently, the list isn't very useful.
This change adds two tables.

* The checkers
* The aliases

For each checkers, we provide extract info:

* the severity. Taken from codechecker - https://github.com/Ericsson/codechecker/blob/master/config/checker_severity_map.json
* if the checker has an autofix or not

I used the cvs format for the table because:
* it is easy
* the data could be reused by other tools (we could move
that into a separated / generated file at some point)

Reviewers: alexfh, jdoerfert, jfb, lebedev.ri, Eugene.Zelenko

Subscribers: dexonsmith, wuzish, nemanjai, kbarton, arphaman, lebedev.ri, whisperity, Eugene.Zelenko, JonasToth, JDevlieghere, xazax.hun, cfe-commits, #clang-tools-extra

Tags: #clang

Differential Revision: https://reviews.llvm.org/D36051