feat: Migrated to TransactionExtension

[Klapeyron]

Description

This PR migrates SignedExtensions to TransactionExtensions.

Checklist

• Commit sequence broadly makes sense and commits have useful messages.
• The size limit of 400 LOC isn't needlessly exceeded
• The PR refers to a JIRA ticket (if one exists)
• New tests are added if needed and existing tests are updated.
• New code is documented and existing documentation is updated.
• Relevant logging and metrics added
• Any changes are noted in the changelog.md for affected crate
• Self-reviewed the diff

[AmbientTea]

Can you provide some context for these changes and why we need them?

[Klapeyron]

It is a building block for possible features we may implement around this functionality. In the past, SignedExtensions didn't had a notion of a weight, so by design had to be cheap in execution. Now it is changing, so we can write custom extensions that may add additional data to the extrinsics and perform additional computation while transaction is in the transaction queue, for instance modify origin that will be used to dispatch this extrinsic.
Out of already implemented extensions are for instance options to pay for transaction fees with custom tokens,not paying for dispatch for certain origins or converting ethereum transactions to substrate ones etc.