qca: add options for head, qt5, tests, api docs and building all plugins

@mikemcquaid Do you think all of the plugins should just be `:recommended` (excepting `qca-ossl` which should always be built), since they all successfully build?
If a user finds that `qca` is having issues after install, shouldn't they have the option to run the test suite, regardless of whether there is one (or even more) known failing tests? Otherwise, they would have to drop back to building from source themselves outside of Homebrew, e.g. with `brew sh`, etc.