[epic] Tag support

[rufuspollock]

trafficstars

Obsidian has tags of from #xyz. Blogs traditionally have tags - cf #35.

How could/would we incorporate tag support in flowershow.

Ideas

• [ ] parsing out tags from pages and adding to frontmatter
• [ ] creating home pages for tags at e.g. /tags/{tag-id} which list all pages with that tag

[avinashkanaujiya]

when will it be supported?