Optional markdown descriptions

[bloodripelives]

Related to #709, I imported bookmarks from Shaarli which contain markdown that is entered as description, so I set my personal instance up to accomodate that by editing line 49 of bookmark_list.html to <div class="markdown">{% markdown bookmark_item.description %}</div>. I understand this isn't a behaviour that would be useful to people using automatically generated descriptions, and it's not a big deal to change manually after any updates, but would markdown descriptions be possible for it to be added as an option that could be toggled in settings?

[sissbruecker]

Maybe, though that could result in side-effects when automatically loading descriptions from websites. Those could contain characters that are then interpreted as markdown, or they could contain an HTML tag that the markdown renderer accepts. It's possible to detect whether a description was entered manually or comes from a website, so maybe website descriptions should never be rendered as markdown. Unfortunately that information is lost when exporting an re-importing bookmarks, so that might be harder to solve.