Fix URI validation

[KellerFuchs]

The current code rejects perfectly valid URLs, due to uri.host != nil.

More generally, Elixir's parser is not validating. I will investigate using ex_uri for that purpose.
@annwenn Would ex_uri be an acceptable dependency to pull in?

due to uri.host != nil

Yes, so people don't fill the database with garbage. But alas it also rejects aliased domains.

I will investigate using ex_uri for that purpose

Yeah of course, poke around with ex_uri

Would ex_uri be an acceptable dependency to pull in?

Once the aforementioned poking will produce results, we'll think about that (I'm not fundamentally opposed, though)

[KellerFuchs]

due to uri.host != nil

Yes, so people don't fill the database with garbage. But alas it also rejects aliased domains.

Yes, I didn't say we should not do validation at all.

The specific case that made me investigate was that I tried to shorten a data URI =^.^'=