Only open status on left mouse press

Currently, the getting started text fails WCAG standards for color contrast by a lot. Especially on the part overlapping with the elephant graphic which is nearly unreadable even for users with 20|20 vision. This change doesn't fix the elephant overlap but at least makes the text meet AAA WCAG Small Text color contrast standards, making it easier to read.

https://github.com/alin-rautoiu/mastodroid/issues/23

fix up spoilers

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

in the background instead. Should fix delay where blocked person
can interact with blocker for a short time before background job
gets processed

Fix `invisible` CSS class

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

background as well since it's a computationally expensive

now return empty hash instead of throwing a 404 error. When following,
merge into timeline will filter statuses

Textarea: fix clicking on name suggestions

This was broken in c3e9ba6a, which added an onBlur to hide the
suggestions when the textarea loses focus. Unfortunately, this fired
even when the textarea lost focus to its own suggestions box, and that
meant that onSuggestionClick is never called.

Setting a short window in which onSuggestionClick can still happen
before hiding the suggestion area ensures that clicking still works,
while still hiding the suggestions if the user clicks on something else.