Support settings custom search path

[levkk]

1. Add search_path configuration open to shards.
2. Fix showing incorrect shard when setting a shard to an unsupported number (just a display error bug).

[minhnguyenvan95]

MR have conflicts

[minhnguyenvan95]

2024-08-21T07:31:04.106968Z ERROR ThreadId(04) pgcat::pool: Shard 0 down or misconfigured: TimedOut    
2024-08-21T07:31:04.107054Z ERROR ThreadId(04) pgcat::pool: Could not validate connection pool    

I've tried to run the code but Timeout Error shown

The code seems like sample code GPT generated

[minhnguyenvan95]

Sorry it's my bad I add the options code to set search_path after the end of \0

[djalmajr]

Any news about that? 🥲