Adding network selection dropdown

[jerrodcodes]

This is intended on adding a network option within the scaffold to select between localhost, devnet, testnet, and mainnet.

[DonnySolana]

checking back in - how are we looking on the updates discussed?!

1. is a page reload necessary when we have state? - when using the drop down and changing the network?
2. for me the drop down acts funny and bounces a bit when rendering, is this something that can be fixed?

Id like to keep the continuity and responsiveness of the app, as dynamic and modular as possible given the context of the toolset being used. Hit me up on any channel if you have a chance to circle back!

[DonnySolana]

please get latest and re-request if desired to merge into latest wallet updates