Added smoke tests for dynamic fee monitoring

[timbrinded]

What does it do?

Adds new smoke test suite for dynamic-fees added in #1765

What important points reviewers should know?

• Test currently skips execution for any chain < RT2100 or not Moonbase (since we are delaying roll out to other chain types)
• Last test is skipped until we add BaseFee to emulated block header via substrate RPC

Run with:

npm run smoke-test:alphanet -- -- --grep S550

What value does it bring to the blockchain users?

On-going monitoring of baseFee calculation to make sure users are being fairly charged as expected.

[notlesh]

This is the lossy part of the equation, as expected. What could be useful is to show that the loss (the truncation) here is always less than some amount.

[notlesh]

...or maybe not, that might just look very redundant...

[timbrinded]

Have added a new test which checks that fee charged = gas used * weight_to_gas const.

I think this isn't what you were exactly asking for, but by inference we have enough coverage of the individual components that fee->gas has been derisked for it to be low concern.

[notlesh]

LGTM. I'd still like to see a precision test where we take block's extrinsics -> exact fee and compare to on-chain, but we can rethink that later. I also think it's useful to intentionally not care about that and focus on the direction of change (as done here).