Add a Tag Type property to Tags

[essenbee]

I think it would be useful for clients to know what category of thing a given tag represents - for example Programming Language (C#, C, C++, F#, Rust etc), Stream Language (English, German, etc) and Framework (.Net Core, Vue.js, etc). A new column should be added to the Tags table for this, along with a supporting table of TagCategories. Then the Admin pages should be updated to allow administrators to categorize tags. The tag category should be mandatory.

This would allow clients to display tag choices grouped by type, like this:

(example above using Adaptive Cards)

Other categorizations might be useful, but these 3 should be supported at minimum, along with Other to account for tags where its not obvious which category the tag falls into..