Bellatrix Release Candidate (v1.2.0-rc.1) - #2896

Co-authored-by: Mikhail Kalinin <noblesse.knight@gmail.com>

Ensure that the SSZ object classes are ordered

Optimistically import any post-merge block

Convert sets to sorted lists prior to sampling

Require fork choice to run before proposal

minor patch to bytes formatting in capella

This reverts commit ac7267c.

This reverts commit e2cbdb2.

Optimistic Sync: remove INVALID_TERMINAL_BLOCK

bellatrix-p2p: fix a typo

bump milagro bls binding version

Update proposer score boost

…-test

Add invalid large withdrawable epoch test

* Ignore subset aggregates

When aggregates are propagated through the network, it is often the case
that a better aggregate has already been seen - in particular, this
happens when an aggregator has not been able to include itself in the
mesh and therefore publishes an aggregate with only its own
attestations.

This new ignore rule allows dropping all aggregates that are
(non-strict) subsets of aggregates that have already been seen on the
network. In particular, it does not mandate dropping aggregates where a
union of previous aggregates would cause it to become a subset).

The logic for allowing this is based on the premise that any aggregate
that has already been seen by a peer will also have been seen by its
neighbours - a subset aggregate (strict or not) brings no new value to
the aggregation algorithm, except in the extreme edge case where you
could combine several such sparse aggregates into a single, more dense
"combined" aggregate and thus use less block space.

Further, as a small benefit, computing the `hash_tree_root` of the full
aggregate is generally not done -however, `hash_tree_root(data)` is
already done for other purposes as this is used as index in the beacon
API.

* add subset ignore rule to sync contributions as well

* typo

* Remove API restrictions

* Update optimistic.md

* deprecate `BeaconBlocksByRange.step`

The `step` parameter has not seen much implementation in real life
clients which instead opt to request variations on a few epochs at a
time (instead of interleaving single blocks, entire epochs are
interleaved).

At the same time, supporting `step` on the server side brings several
complications: more complex bounds checking logic, more complex loading
of blocks from linear storage (which presumably stores all blocks and
not just certain increments).

This PR suggests that we deprecate the whole idea. Backwards
compatibility is kept by simply responding with a single block when
`step > 0` - this is allowed by the spec and should thus be handled
gracefully by requesting clients already, should there exist any that
use larger step counts.

Removing `step` now allows simplifying the EL-CL protocol for serving
execution data from the EL to avoid double storage.

* Update specs/phase0/p2p-interface.md

Co-authored-by: Danny Ryan <dannyjryan@gmail.com>

Co-authored-by: Danny Ryan <dannyjryan@gmail.com>