Implement /tags etc.

[FelixSFD]

• /tags: Get the tags on the site.
• /tags/{tags}/info: Get tags on the site by their names.
• /tags/moderator-only: Get the tags on the site that only moderators can use.
• /tags/required: Get the tags on the site that fulfill required tag constraints.
• /tags/synonyms: Get all the tag synonyms on the site.
• /tags/{tags}/faq: Get frequently asked questions in a set of tags.
• /tags/{tags}/related: Get related tags, based on common tag pairings.
• /tags/{tags}/synonyms: Get the synonyms for a specific set of tags.
• /tags/{tag}/top-answerers/{period}: Get the top answer posters in a specific tag, either in the last month or for all time.
• /tags/{tag}/top-askers/{period}: Get the top question askers in a specific tag, either in the last month or for all time.
• /tags/{tags}/wikis: Get the wiki entries for a set of tags.