feat: [shard-distributor]Compress data before writing to ETCD

[gazi-yestemirova]

What changed?

• Update Shard-distributor Store config to accept Compression field, to set the compression type. Defaults to none
• Add Compress() method to encode data with snappy compression
• Compress executor state, reported shards and assigned state before writing to etcd
• Extend unit-tests with compression logic check

Why?
To reducing storage footprint

How did you test it?
unit-tests and local testing

Potential risks
N/A

Release notes

Documentation Changes

[dkrotx]

This way, with explicit compressionType it is required to specify it every time.
I think it's better to not focus on which algorithm we use (for the exported function) since it's not that we're building a generic compressor - we're building serializer of data for etcd. We can decide internally which algorithm we use, the only thing we need to know is to whatever we need to compress the data.

I would suggest something like RecordWriter which initializes with compress or not (from the config?) and then does that on .Write() or something. But .Write internally already knows it uses "snappy" or whatever.
Otherwise you need to do tricks like

switch strings.ToLower(compressionType) {
	case "", "none":
```.