Add maxdrift directive to set the maximum assumed drift of the clock,
which sets the maximum frequency offset chronyd is allowed to use to
to correct the drift.
Similarly to unreachable sources and falsetickers, try to replace
sources with distance larger than the limit set by the maxdistance
directive with a newly resolved address of the hostname.
Split and convert the manual into four AsciiDoc documents, a document
about installation and three documents in the manpage type for
chrony.conf, chronyd and chronyc. The minimal man pages that were
maintained separately from the manual are replaced by full man pages
generated from AsciiDoc. Info files will no longer be provided.
Some parts of the manual are rewritten, updated or trimmed. The
introduction chapter is partially merged with README. The chapter about
typical operating scenarios is included in the chrony.conf man page.
