Migrate from redigo to goredis

[kerak19]

Replaced redigo client with goredis one.

@benmanns what is the significance of GetConn and PutConn ? I've removed them because of redis lib change, but they can be recovered if that's important (using https://pkg.go.dev/github.com/go-redis/redis/[email protected]#Client.Conn).

Fixes #69