contracts: Allow indeterministic instructions off-chain

[athei]

Fixes https://github.com/paritytech/substrate/issues/12063 Fixes https://github.com/paritytech/substrate/issues/11367

Some points apart from what was mentioned in the issues. Also mentioned in updates to the README:

• A indeterministic code can never be instantiated. Even during an off-chain execution where the change wouldn't be persisted in storage.
• The set_code API call does not allow setting to an indeterministic contract. With the exception of the root call. We trust governance here.
• The only allowed workflow is: upload_call-> bare_call. The runtime API also does not allow executing indeterministic code. A runtime need to build their own abstraction around pallet_contracts::Pallet::bare_call.
• The default schedule does disable this feature (will fail at upload).

cc @kvinwang @h4x3rotab

[h4x3rotab]

Fantastic! Thank you for the support. We cannot wait to test running serde_json in ink! 😎

[athei]

bot merge

[paritytech-processbot[bot]]

Error: "Check reviews" status is not passing for https://github.com/paritytech/cumulus/pull/1794

[athei]

bot merge