Add CT API endpoint strings (#254)
Add CT API endpoint strings (#254)

* Add CT API endpoint strings

* Change URL paths to use api endpoint strings

* Add missing / to CTV1Prefix

* Undo the last couple of commits

Because the new APIEndpoint type messes up the types of the path
strings, and there is no pretty and readable way to combine the two.
Which is fine, as the paths and the new string-enum things are meant for
different purposes.

* Add warnings to link API endpoints and URL paths.

daviddrysdale/certificate-transparency-go,google/certificate-transparency-go,google/certificate-transparency-go,google/certificate-transparency-go,daviddrysdale/certificate-transparency-go,RJPercival/certificate-transparency-go,RJPercival/certificate-transparency-go,RJPercival/certificate-transparency-go,daviddrysdale/certificate-transparency-go