Support every JSON Schema format for Draft 4

[jviotti]

These are the ones that are missing right now: https://github.com/sourcemeta/jsontoolkit/blob/46846a4bafb5664b3fc7ae08e47c415639084c44/test/jsonschema/officialsuite.cc#L191-L192, which should be implemented here: https://github.com/sourcemeta/jsontoolkit/blob/46846a4bafb5664b3fc7ae08e47c415639084c44/src/jsonschema/default_compiler_draft4.h#L360-L398.

Some of them are somewhat URI related, like hostname and ipv6, which might need to first be implemented in URI Kit, which has #710 as a requirement. For example, for ipv6 we likely want a full blown IPv6 parser in place?