Rewrite some of the paragraph to make them (hopefully) clearer, reorder
the feature list in a 2-level structure for more legibility, reference
the IRC channel, and other minor wording changes.
This patch adds dovecot support to the chasquid daemon, using the
internal dovecot library added in previous patches.
Dovecot support is still considered EXPERIMENTAL and may be reverted, or
changed in backwards-incompatible ways.
The patch also adds the corresponding integration test, which brings up
a dovecot server with a custom configuration, and tests chasquid's
authentication against it. If dovecot is not installed, the test is
skipped.
One of the command sequences was not indented enough, so it appears as
text instead of code.
This patch fixes that by surrounding it with ``` to mark it explicitly
as a code block.
