feat: sort packed attestations by total effective balance (#7673)

**Motivation**

- packed attestations are currently sorted by new seen attesters, should
be by effective balance
- not enough metrics when producing packed attestations

**Description**

- for electra, retain up to 8 attestations per group. When getting
attestations, we also get up to 8 of them (instead of 3)
- track packed attestations by new seen effective balance
- reevaluate every attestation after an attestation is included, see
`getMostValuableAttestation()`. This means there is no useless
attestations included
- add a lot of metrics:
  - committee bits for each packed attestation
  - total committee members of each packed attestation
  - non-participation of each packed attestation
- distance from block slot to attestation slot for each packed
attestation
  - total effective balance for each packed attestations
  - scanned slots and termination reason
  - scanned attestations per scanned slot
  - returned attestations per scanned slot
  - total slots in pool at the time of producing block
  - total consolidations

Closes #7544

**Testing**

- see some metrics here
#7646 (comment)
- performance are the same on hoodi prod node

<img width="846" alt="Screenshot 2025-04-08 at 16 09 17"
src="https://github.com/user-attachments/assets/7ffb3bcb-7774-4383-b2e7-da1065ff8f97"
/>

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Co-authored-by: Tuyen Nguyen <[email protected]>
Co-authored-by: Nico Flaig <[email protected]>

Author: twoeths