Add missing LICENSE files to several workspace crates

[musicinmybrain]

In the case of crates published on crates.io, like rioterm, rio-proc-macros, teletypewriter, etc., this fixes missing license text in the published crates. Normally, I would just use symbolic links to the top-level LICENSE file in a PR like this, but I followed the lead of existing license files like corcovado/LICENSE and made copies instead.

I also added the LICENSE file to frontends/wasm. It isn’t published on crates.io, and I don’t entirely understand how to use it, but I assumed it was the right thing to do there as well.

Including the license text with published crates is necessary so that people can comply with the chosen MIT license, which says:

rio/LICENSE

Lines 12 to 13 in 73f0158

	The above copyright notice and this permission notice shall be included in all
	copies or substantial portions of the Software.

[raphamorim]

Thank you @musicinmybrain