SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
This is a wrapper around a string representing a domain name (such as
"example.com"). It never has a trailing dot.
For now, this class doesn't do much except wrap the raw string. Subsequent
commits will add or move more functionality to it.
