Replica promote (#12090)

## Problem

This PR is part of larger computes support activity:

https://www.notion.so/neondatabase/Larger-computes-114f189e00478080ba01e8651ab7da90

Epic: https://github.com/neondatabase/cloud/issues/19010

In case of planned node restart, we are going to 
1. create new read-only replica
2. capture LFC state at primary
3. use this state to prewarm replica
4. stop old primary
5. promote replica to primary

Steps 1-3 are currently implemented and support from compute side.
This PR provides compute level implementation of replica promotion.

Support replica promotion

## Summary of changes

Right now replica promotion is done in three steps:
1. Set safekeepers list (now it is empty for replica)
2. Call `pg_promote()` top promote replica
3. Update endpoint setting to that it ids not more treated as replica.

May be all this three steps should be done by some function in
compute_ctl. But right now this logic is only implement5ed in test.

Postgres submodules PRs:
https://github.com/neondatabase/postgres/pull/648
https://github.com/neondatabase/postgres/pull/649
https://github.com/neondatabase/postgres/pull/650
https://github.com/neondatabase/postgres/pull/651

---------

Co-authored-by: Matthias van de Meent <matthias@neon.tech>
Co-authored-by: Konstantin Knizhnik <knizhnik@neon.tech>

libs/walproposer/src/api_bindings.rs

@@ -439,6 +439,7 @@ pub fn empty_shmem() -> crate::bindings::WalproposerShmemState {
         currentClusterSize: crate::bindings::pg_atomic_uint64 { value: 0 },
         shard_ps_feedback: [empty_feedback; 128],
         num_shards: 0,
+        replica_promote: false,
         min_ps_feedback: empty_feedback,
     }
 }