Provide RtpState at construction when restoring an RTP module

When a suspended stream was recreated, its previous state was applied
with SetRtpState() and SetRtxState() right after construction. This
required state to be mutable that otherwise could be const, which in
turn required a lock for every read on the encoder queue.

* Add rtp_state and rtx_rtp_state to RtpRtcpInterface::Configuration.
* Apply it when constructing RTPSender and ModuleRtpRtcpImpl2.
* RtpVideoSender and AudioSendStream, via ChannelSend, now pass the
  suspended states at creation.
* Remove SetStartTimestamp(), SetRtpState() and SetRtxState() from
  RtpRtcpInterface, ModuleRtpRtcpImpl2, as well as
  RTPSender::SetRtxRtpState().
* Deprecate RTPSender::SetTimestampOffset() and SetRtpState(). Once
  direct users of RTPSender have migrated, they can be removed and the
  timestamp offset made const.

Bug: webrtc:42223727
Change-Id: Idad26fe1205c1288a3455865dfb79027ed7f83da
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/507320
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Commit-Queue: Tomas Gunnarsson <tommi@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#48831}