util.watchdog: Allow :reset() to restart a cancelled watchdog

util.watchdog: Update to use "new" util.timer API When this module was written, it wasn't possible to cancel or reschedule a timer. Times have changed, and we should take advantage of those new methods. This module becomes a very thin wrapper around util.timer now, but I'd argue it's still a very common and useful concept/abstraction to have around. Possible API change: this removes the 'last_reset' field of the watchdog. This was never really intended as a public thing, and I can't find any code that uses it, so I consider removal to be safe.

Merge 0.12->trunk

Added tag 0.12.1 for changeset 252ed01896dd

net.server: Fix multiple return values return foo and foo() crops multiple return values to a single one, so any second return values etc were last, mostly error details. Introduced in 7e9ebdc75ce4

mod_saslauth: Advertise channel bindings via XEP-0440 This is useful when there's more than one channel binding in circulation, since perhaps there will be varying support for them.

mod_admin_shell: Include last (mod_cron) task run time in module:info() Don't think this is otherwise shown anywhere outside of debug logs

util.prosodyctl.shell: Print errors in red to highlight them

mod_admin_shell: Drop unused argument [luacheck]

mod_admin_shell: Show bound ports in module:info I.e. the subset of port:list() relevant to the specified module.