[Tracking issue] open regions in batches

[WenyXu]

What type of enhancement is this?

Performance, Refactor, Tech debt reduction

What does the enhancement do?

• feat: add RawEntryReader and OneshotWalEntryReader trait #4027
• Refactor LogStore, Add the WalEntryReader to decode raw WAL entries into upper-level WAL entries refactor(log_store): remove associated type Namespace and Entry in LogStore #4038
• Add the RawEntryReader to read undecoded raw WAL entries feat: implement the LogStoreRawEntryReader and RawEntryReaderFilter #4030
• feat: implement WalEntryDistributor, WalEntryReceiver #4031
• Open a region in the background feat: open region in background #4052
• Add the handle_batch_open_requests to the RegionEngine trait and implement the handle_batch_open_requests method for the mito engine feat: implement the handle_batch_open_requests #4075
• Add the handle_batch_open_requests to the region server feat: invoke handle_batch_open_requests #4107

The whole picture:

Implementation challenges

No response