Add Golang client for Stellar RPC #78

Job	Run time
Build (ubuntu-latest, x86_64-unknown-linux-gnu, amd64)	3m 14s
Integration tests (ubuntu-20.04, 21)	6m 44s
Build (ubuntu-latest, aarch64-unknown-linux-gnu, arm64)	4m 1s
Integration tests (ubuntu-20.04, 22)	7m 6s
Build (macos-latest, x86_64-apple-darwin, amd64)	5m 27s
Integration tests (ubuntu-22.04, 21)	6m 23s
Build (macos-latest, aarch64-apple-darwin, arm64)	8m 9s
Integration tests (ubuntu-22.04, 22)	7m 2s
Build (windows-latest, x86_64-pc-windows-gnu, amd64)	12m 48s
Unit tests (ubuntu-20.04)	5m 6s
Unit tests (ubuntu-22.04)	4m 7s
	1h 10m 7s

Provide feedback