feat: impl albums

[AndrielFR]

• add InputMedia struct.
• add send_album, reply_album and respond_album methods.

[Lonami]

I had in mind a slice of InputMedia. But perhaps using a Vec is okay, as it means we can take ownership and reduce clones. Not sure what's best.

[AndrielFR]

I think Vec is the best option right now

[Lonami]

Not entirely convinced. But we can definitely merge it like this for the time being and see how it feels.

[AndrielFR]

Ok.

[dimentyy]

Isn't InputMedia just a smaller version of InputMessage? Why not use InputMessage?

[Lonami]

Isn't InputMedia just a smaller version of InputMessage? Why not use InputMessage?

Yes, but this was deliberate, because not all messages are valid for album media.

I think a new type is justified, because albums require media to be set, while InputMessage don't. We would have to add even more validations, and then return Err, and the current Error type used by the client methods is already complex enough. So I'm not sure it's worth reusing the type.

What I did consider however, was using InputMedia for attaching it to the InputMessage. But that's a different problem entirely.