add check metadatahash signed extension

[clangenb]

The official documentation recommends to not enable the metadata-hash computation at build time by default because it needs to compile the runtime twice (which doesn't double the build-time). Hence, it is advisable to feature gate it to speed-up regular build-times. However, I am not sure if it is worth to increase the build-complexity because of this. The fellowship has feature gated it like this.

On my machine, I get the following build times for a collator build (partial build, starting from roughly same crate):

• ~1630 crates in total = 14 min 53s build time
• ~1401 crates in total = 12m 17s build time

Hence, the difference is kind of small, and I don't think it is worth it. However, if we establish the concept of an onchain-release build anyhow, we can change that in the future.

Todo:

• first merge polkadot-v1.13.0 #296

[brenzi]

guess we need to fix rpc method for fee details somehow as well? maybe on worker side?

thread 'main' panicked at 'enclave RA registration must be successful to continue: Custom("Fee Details for the registration of the enclave is None !")', service/src/main_impl.rs:493:28
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace