Link reporter should ignore anchor links

www.agileplannerapp.com/boards/173808/cards/6121

Anchor links link to content within the page, hence we should not report them as broken.
Also contains a data migration to remove anchor links from existing link reports.
@danielroseman - when full URLs with anchor links are present, we should check those and shouldn't ignore them as the page should return `200`, or did you mean *aren't extracted*?