Normalize Gerrit ACL documentation

It turns out that while changes to Gerrit ACLs from the WebUI will
create "Git config" format files which look somewhat like
traditional INI files with hard-tab indentation and other
unpleasantness, Gerrit will interpret more traditional INI files as
ACLs just fine and merge them to refs/meta/config unaltered. Adjust
the examples to look like the sorts of INI files with which our
developers are more familiar, and apply some other helpful
normalization like alphabetizing the section and key orders,
removing redundant default values or other no-ops, et cetera.

Change-Id: I3b9dad7b7beb05427eb4011fa6dad2a6dd4cbe72
Merge "Normalize Gerrit ACL documentation"