As there will be plenty of types, it will be better to split it up.
Also learned something about self::<submodule> :).
Insert and and update should be hand-implemented just to see how it's
working. Then there should be some investment to auto-generate this
with `gsl`. Once the latter works ... I could auto-generate all apis,
or adjust the go generator to create rust instead.
Depends on what will be faster ... .
There is a central `YouTube` type which helps constructing various
sub-builders, which in turn provide individual functions.
Architecturally, it's very similar to the go implementation, but
more efficient memory wise.
