Replace INTERVALS_PER_SLOT with explicit slot component times

[eserilev]

Issue Addressed

ethereum/consensus-specs#4476

Additional Info

This change affects many critical paths in lighthouse and should not be merged until after 8.0.0

the Ethereum kurtosis package is working to support this change here: ethpandaops/ethereum-package#1168

[dapplion]

Should this change consider that the slot time will change in the future? Or that's to be handled in a future PR

[eserilev]

Should this change consider that the slot time will change in the future? Or that's to be handled in a future PR

I think we should handle that in a future PR to keep this diff here as small as possible

[jimmygchen]

Hey @eserilev

I've reviewed the PR, please see my comments - there are a few issues but most of the changes look safe and I think we're close to merging this!

Let me know if you'd like to discuss on any of the comments or if they're unclear.

[michaelsproul]

LGTM. Peer reviewed with @jimmygchen

[mergify]

Merge Queue Status

🚫 The pull request has left the queue (rule: default) at 3178e85

This pull request spent 1 minute 17 seconds in the queue, with no time running CI.

Reason

The pull request #7944 has been manually updated

Hint

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[mergify]

Merge Queue Status

✅ The pull request has been merged at e362f41

This pull request spent 33 minutes 11 seconds in the queue, including 31 minutes 26 seconds running CI.
The checks were run on draft #8728.

Required conditions to merge

• check-success=local-testnet-success
• check-success=test-suite-success

[eserilev]

thanks guys!