* OEmbed support for PreviewCard

* Improve ProviderDiscovery code failure treatment

* Do not crawl links if there is a content warning, since those
don't display a link card anyway

* Reset db schema

* Fresh migrate

* Fix rubocop style issues
Fix #1681 - return existing access token when applicable instead of creating new

* Fix test

* Extract http client to helper

* Improve oembed controller

This commit fixes hashtag_html so it correctly handles matches with multiple hash-signs.

Bug located by @over9001, initial fix suggested by @nightpool.

* fix character escaping in URL

* add tests

* put a comma after the last item

* add HTML escape test

Fix username styling regression introduced in #1063
Fix report screen background regression introduced in #1415

When transmitting data in a HTML-encoded element like <content type="html" />,
relying on newlines being preserved is not wise, since HTML by itself
does not care for newlines - it cares for <p> and <br>

Additional fix: reset NSFW toggle after sending toot

* significant improvement in microformats markup

This is a huge improvement and I believe will close #965.

Had these microformats reviewed by others in the community to help
ensure they are at least correct, if not complete.

I did not want to change the structure of the page, and so there it does
not fully mark up the entire ancestry chain, or reply chain, only the
direct decendants and direct ancestors are correctly associated, but
this is likely fine as the most important bit is to have access to the
urls for those toots which are now correctly fetchable.

* improve code climate

* trying to pass code climate tests

* code climate

* fix p-summary for content warning posts

* fix error introduced when merging via github

Federate spoiler_text using warning attribute on <content /> instead of a <category term="spoiler" />
Clean up schema file from accidental development migrations

affected, replaced onClick handler with onMouseUp/Down to detect text
selection not trigger onClick handler then

to sign in page after sign up instead of root path which redirects to /about

timeline reload in UI, other small fixes

as well as formatting of content