Baker: manager operations number and fees in block event

What

Improve the baker events when injecting a block by adding the number of manager operation in the blocks and the sum of their fees going from

to

Why

User might want to have a bit more information about the block baked.

How

Recover the number of manager operations and their fees when forging the block and output it in the injection event

Manually testing the MR

- Run a sandbox node
- Init a sandbox client
- octez-activate-alpha
- octez-client gen keys alice
- octez-client gen keys bob
- octez-client --wait none transfer 1000000 from bootstrap1 to alice --burn-cap 0.07
- octez-client --wait none transfer 1000000 from bootstrap2 to bob --burn-cap 0.07
- octez-baker-alpha run remotely

You should see the number of manager operations count and fees in the first injected block logs

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