Network pool

[janaakhterov]

hiero-ledger/hiero-sdk-go#113

At the moment the SDK only establishes one connection per node. This can be a limiting factor when someone wants to submit many requests since the singular connection can be the bottleneck. What this discussion is proposing is that each node maintains a pool of connections and cycles which connection it uses per request. The pool size should definitely be configurable perhaps through a Client.setPoolSize(int) method.