Only resend webmentions if `not_supported` after 2 weeks
To prevent spamming Telegraph with requests to Webmention servers that almost certainly have not implemented Webmentions since the last time I sent them a webmention, we can add a time delay between sending requests.
We can do this by adding a new
WebmentionValidator that can prevent
the sending of a webmention if the
WebmentionRepository hasn't seen it
sent in the last two weeks.
If a site is going to add the capability for Webmentions, two weeks may be a safe bet to allow them a grace period before notifying them.
This timestamp gets automagically updated when a new Webmention is attempted - regardless of whether it fails again, or succeeds.
Closes #76 (closed).