Enum for available licences

[seanbudd]

Have we considered having some kind of auto-generated license URLs from an enum
of standard license versions?

Most are using GPL2, with some GPL3, Apache, and probably MIT.

Having an enum for license types, which then fills in an automatic URL, then
providing an enum key for "other" with a manual URL expected, might make this
easier.

Originally posted by @XLTechie in nvaccess/nvda#14683 (comment)