Update to Polkadot 0.9.11 and fix XCM traits

[joao-paulo-parity]

This in incomplete. I tried to get it as far as I could, but then I don't know how to solve the following:

error[E0432]: unresolved import `polkadot_overseer::AllSubsystems`
   --> client/collator/src/lib.rs:330:26
    |
330 |     use polkadot_overseer::{AllSubsystems, HeadSupportsParachains, Overseer};
    |                             ^^^^^^^^^^^^^
    |                             |
    |                             no `AllSubsystems` in the root
    |                             help: a similar name exists in the module: `MapSubsystem`

error[E0599]: no function or associated item named `new` found for struct `Overseer` in the current scope
   --> client/collator/src/lib.rs:388:38
    |
388 |         let (overseer, handle) = Overseer::new(
    |                                            ^^^ function or associated item not found in `Overseer<_, _>`

error[E0599]: no associated item named `Connected` found for struct `Handle` in the current scope
   --> client/collator/src/lib.rs:403:37
    |
403 |             overseer_handle: OverseerHandle::Connected(handle),
    |                                              ^^^^^^^^^ associated item not found in `Handle`

Overseer and AllSubsystems seems related to paritytech/polkadot#3874. Right now I don't have enough context to work on those changes. Feel free to take over this work.

It might be the only piece missing to make paritytech/substrate#9749 's dependent cumulus check pass.

closes #634

[bkchr]

Superseded by: #636