message: specs: Remove outdate portions
  This cleans up specs. Specifically:
  We no longer allow right padding on frames.
  Specify that all frames must be parseable in a batcher transaction
diff: @@ -299,9 +299,8 @@ Batcher transactions are encoded as `version_byte ++ rollup_payload` (where `++`
  | 0 | `frame ...` (one or more frames, concatenated) |
  Unknown versions make the batcher transaction invalid (it must be ignored by the rollup node).
  -
  -The `rollup_payload` may be right-padded with 0s, which will be ignored. It's allowed for them to be
  -interpreted as frames for channel 0, which must always be ignored.
  +All frames in a batcher transaction must be parseable. If any one frame fails to parse, the all frames in the
  +transaction are rejected.
  > **TODO** specify batcher authentication (i.e. where do we store / make available the public keys of authorize batcher
  > signers)
  