Store logical replication origin in KV storage (#7099)

Store logical replication origin in KV storage

## Problem

See  #6977

## Summary of changes

* Extract origin_lsn from commit WAl record
* Add ReplOrigin key to KV storage and store origin_lsn
* In basebackup replace snapshot origin_lsn with last committed
origin_lsn at basebackup LSN

## Checklist before requesting a review

- [ ] I have performed a self-review of my code.
- [ ] If it is a core feature, I have added thorough tests.
- [ ] Do we need to implement analytics? if so did you add the relevant
metrics to the dashboard?
- [ ] If this PR requires public announcement, mark it with
/release-notes label and add several sentences in this section.

## Checklist before merging

- [ ] Do not forget to reformat commit message to not include the above
checklist

---------

Signed-off-by: Alex Chi Z <chi@neon.tech>
Co-authored-by: Konstantin Knizhnik <knizhnik@neon.tech>
Co-authored-by: Alex Chi Z <chi@neon.tech>

libs/pageserver_api/src/key.rs

@@ -1,6 +1,7 @@
 use anyhow::{bail, Result};
 use byteorder::{ByteOrder, BE};
 use postgres_ffi::relfile_utils::{FSM_FORKNUM, VISIBILITYMAP_FORKNUM};
+use postgres_ffi::RepOriginId;
 use postgres_ffi::{Oid, TransactionId};
 use serde::{Deserialize, Serialize};
 use std::{fmt, ops::Range};
@@ -38,6 +39,9 @@ pub const RELATION_SIZE_PREFIX: u8 = 0x61;
 /// The key prefix of AUX file keys.
 pub const AUX_KEY_PREFIX: u8 = 0x62;
 
+/// The key prefix of ReplOrigin keys.
+pub const REPL_ORIGIN_KEY_PREFIX: u8 = 0x63;
+
 /// Check if the key falls in the range of metadata keys.
 pub const fn is_metadata_key_slice(key: &[u8]) -> bool {
     key[0] >= METADATA_KEY_BEGIN_PREFIX && key[0] < METADATA_KEY_END_PREFIX
@@ -587,6 +591,37 @@ pub const AUX_FILES_KEY: Key = Key {
     field6: 2,
 };
 
+#[inline(always)]
+pub fn repl_origin_key(origin_id: RepOriginId) -> Key {
+    Key {
+        field1: REPL_ORIGIN_KEY_PREFIX,
+        field2: 0,
+        field3: 0,
+        field4: 0,
+        field5: 0,
+        field6: origin_id as u32,
+    }
+}
+
+/// Get the range of replorigin keys.
+pub fn repl_origin_key_range() -> Range<Key> {
+    Key {
+        field1: REPL_ORIGIN_KEY_PREFIX,
+        field2: 0,
+        field3: 0,
+        field4: 0,
+        field5: 0,
+        field6: 0,
+    }..Key {
+        field1: REPL_ORIGIN_KEY_PREFIX,
+        field2: 0,
+        field3: 0,
+        field4: 0,
+        field5: 0,
+        field6: 0x10000,
+    }
+}
+
 // Reverse mappings for a few Keys.
 // These are needed by WAL redo manager.