Refactor teerex/sidechain pallet into teebag

[Kailai-Wang]

Context

This PR uses a new pallet teebag to replace teerex + sidechain pallet.

It uses the name teebag because enclave is like a teabag and the pallet is used to manage the teabag.

Additionally:

• it removes the feature skip-ias-verify and changes it to runtime control
• it merges the original teerex and sidechain pallets (version before MS-RSL licence) into one and rewrite/update it - it still has a mixed licence header tho, especially for the parts that I hardly made any changes
• it adds worker_type to allow multiple worker types
• it removes heartbeat for now - we'll need to think about how to deal with it, plus we have the enclave removal extrinsic
• it revamps the Enclave structure, the map uses the T::AccountId as the key, because that's (the only identifier?) guaranteed to be different for each worker and has a native parachain connection
• it moves sgx-verify from crate to mod
• it unifies the tests with and without ias-verify

Some follow-up TODOs - I'll create issues:

• let workers connect to pallet-teebag (while keeping teerex for state reference)
• benchmarking / weights
• remove teerex/sidechain pallet usage in runtime and worker
• runtime upgrade to include the changes, including state migration to clear the teerex state

But before I continue I'd like to see reviews about this refactoring

[linear]

P-443 Refactor teerex/sidechain pallet

[felixfaisal]

Thanks @Kailai-Wang ,In terms of the refactor itself, I don't see any concerns, I don't know much about the attestation process, So from my side it looks good.