Genesis URL should be customizable

[TimoGlastra]

The genesis url is hardcoded in genesis-utils.ts. This should (optimally) be an input paramater after which the app handles downloading of the genesis, or (less optimal, but okay) be a parameter in the downloadGenesis method

aries-mobile-agent-react-native/src/agent/genesis-utils.ts

Lines 12 to 18 in 03c5228

	async function downloadGenesis(): Promise<string> {
	const url = 'http://dev.greenlight.bcovrin.vonx.io/genesis'
	const response = await axios.get(url)
	return response.data
	}

[karimStekelenburg]

I am aware of this. My plan is to add dotenv support so testing on multiple networks will become easier. As the proposed change will only move the hardcoded url from one place to another, I don't think this is a high priority issue (correct me if I'm wrong). Therefore I think it's best to take on this issue and add dotenv support in one go.