MIR: Add numbers encoding

Context

This is continuation of !10689 (merged) and implements encoding for numeric values.

I simply take implementation from tezos_data_encoding library that we may need anyway after rollups come into play (at least I add this dependency in my MRs). Not sure here, but see no reasons for rolling out our own solution yet.

Manually testing the MR

cargo test

Checklist

• Document the interface of any function added or modified (see the coding guidelines)
• Document any change to the user interface, including configuration parameters (see node configuration)
• Provide automatic testing (see the testing guide).
• For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, CHANGES.rst at the root of the repository for everything else).
• Select suitable reviewers using the Reviewers field below.
• Select as Assignee the next person who should take action on that MR