Enhance motion.create_forwarded

[jsangmeister]

see OpenSlides/openslides-client#3527 for context

• add boolean to control which submitter is used: The original one or the forwarding committee
• add boolean to control which number is used: The original one or none

[luisa-beerboom]

Talked with @rrenkert about number option, two points:

• Instead of blanket-setting the number to none if the original number is not selected, the second option should just preserve the current functionality (which does indeed generate a number at times)
• If original is selected and the number already exists in the target meeting, we're appending -1, -2, -3, u.s.w. to it until we arrive at a unique number

[rrenkert]

The forwarding of an "original motion" and its amendmends should not include the following attributes:

• status (falls back to the default workflow's initial state)
• recommendation
• category
• motion block
• comments