Add delete tag endpoint

[nojaf]

I've add a simple endpoint and some steps of how I did it.
Please review and don't be shy to add remarks on the markdown!

[jescalada]

We could also add a section for performance-related considerations. Since we are porting to Go for performance reasons (?), there are times where we don't want to do things exactly like they're done in Python? Maybe we can add some actual examples of rewriting existing logic to make it more efficient or idiomatic.

[jescalada]

This is a second, in-depth review of the guide from going through all the steps as a Go newbie. Feel free to take them or leave them as needed :)

[jescalada]

Guide looks great! Just had some minor wording changes (and index fix).

[dsuhinin]

Looks really good! Nice job!