usedBy is still stored as a string in invites.json to cope with existing
invites with times stored formatted. knz/strtime requires cgo for
strptime, so it has been replaced with the native itchyny/timefmt-go.
this will add an optional validity period to users, where their account
will be disabled (or deleted) a specified amount of time after they
created it.
the web ui has been redesigned with the a17t toolkit, which imo looks a
lot better than bootstrap. This also brought a complete rework of the
web code, which now makes a lot more sense hopefully. the setup page is
still stuck with bootstrap, its not much of a priority but i'll rewrite
it eventually.
web UI now uses modules, and relies less on bodge to make things work.
Also fixes an issue where invites where "failed to send to xx" appeared
in invite form.
Harvey Tindall