Add command 'rit delete cache'

[GuillaumeFalourd]

What would you like to be added:

A command to remove a formula input cache saved.

Why is this needed:

This process is not intuitive for users, as cache values are currently saved locally on the .rit repository, on the /repos directory, at the same level of the formula binary. If someone wants to delete a cache value, it will be necessary to go manually to this folder, check hidden files, and remove the CACHE file. This command would make it easier for users to perform this action.

• Check this box if this issue needs a documentation update

[kashifsoofi]

Can I please attempt this.
Also I am new to Golang & this project so would appreciate some guidance to tackle this.

I started off by copying the delete_repo, I am assuming cache is per repo so we would expect rit delete cache <repo_name>?