Allow several messages to be forwarded at once (for media groups)

[Poolitzer]

The method the bot API will call is forwardMessages. Currently the bot API only allows to forward one message in forwardMessage.

This decision doesn't allow bots to forward (parts of) media groups. If a bot e.g. encounters a media group in a channel and wants to forward it as a group, the bot has to send a new media group. This degrades the user experience, since the link to the channel is lost and the bot has to add it manually to the media caption if it is to persist, not to speak of the view counter which the bot can not replicate even if it wants to. The other solution is to forward each media of a media group, which can lead to 10 updates at once for an user, which they certainly do not appreciate either.

It would be better if a bot can forward multiple messages at once, as the MTProto API and clients support.