Rename ProviderID

[ionut-arm]

I have a feeling that the ProviderID isn't really named appropriately anymore. Provider would probably be a better name, as we use the enum to identify the type of provider we're refering to throughout the stack, not just for managing their IDs

[hug-dev]

Should we also with this issue, refactor the ProviderID type completely? I think we agreed that in the future, if we have multiple providers of the same type, this won't work anymore. Maybe ProviderID should just be a new type composed of a value + a type?

[ionut-arm]

I think this will be painful to change because a lot of things depend on a clear mapping from ProviderID to provider type, but that's more of an incentive to do that sooner before we hardcode even more stuff to that assumption

[hug-dev]

Should think about that in parallaxsecond/parsec-book#83

[ionut-arm]

Should think about that in parallaxsecond/parsec-book#83

Hmm, that's true, I think the stability issue here is related to the interface of the client - how do users specify they want "That particular provider!". At the moment the list is static, in the future it could change. I've written a short comment on the issue above, will close this and raise a more clear issue once we get to it.