Client: Poll wallet provider for current network, and warn if it's not the same as the default provider

[sohkai]

See https://medium.com/metamask/breaking-change-no-longer-reloading-pages-on-network-change-4a3e1fd2f5e7

We could probably do this check only when a user goes to the signing view, since that's the only time we need access to their wallet.

[chris-remus]

Will implement pop-up requiring users to login to wallet on same network as default provider.

[chris-remus]

New flow -

• Indicate browse-only, connected to network, or connection issue state under badge in sidebar
• Connection issue state will show pop-up indicating network mismatch and instructions to fix
• Signer panel will communicate inability to sign and reason, if user makes it that far without logging-into wallet and/or fixing network mismatch

[chris-remus]

@jounih How's this coming along? Please post designs here if they're ready.

[jounih]

Design