Create an AUTHORS file and update README

Move README to README.adoc in preparation to updating

Create an AUTHORS file

List all people who have contributed to mkinitcpio.

The file was created with:

LC_ALL=C git shortlog -se | cut -f2 > AUTHORS

Those with noreply emails have only their names listed.

Fixes #148 (closed)

Update README.adoc

Document development and contributing.

Update the copyright notice and link the new AUTHORS file.

Fixes #119 (closed)

man/*.adoc: update the bugs, authors and copyright notices

Link to the project page on https://gitlab.archlinux.org/archlinux/mkinitcpio/mkinitcpio for the issue tracker instead of bugs.archlinux.org.

Mention the new AUTHORS file and update the copyright notice accordingly.

man/*.adoc: convert to newer AsciiDoc syntax

Convert legacy emphasized text using single quotes to new syntax using underscores. This required using unconstrained quotes for some bold text. For the few placed that need literal single quote characters, use a passthrough macro.

Use one line titles (equals signs in front of the tile instead of underneath them) because my text editor (Kate) does not support syntax highlighting the old syntax.

Properly format labeled lists.

Use sentence case for all section titles. We are not some newspaper.

Wrap lines at 80 characters, because who doesn't love living the past...

The syntax still remains compatible with the asciidoc-py parser and man pages are still the same. The man pages can be generated with both a2x and asciidoctor.