Fallback to infura if no wallet connected

[chrismaree]

If the user has not connected metamask the app should still work to show contract information. It should gracefully use infura directly to show EMP contract info but disable the manage tab until they connect their wallet.

[adrianmcli]

Yeah we can consider doing this, I have two concerns:

1. This means the frontend will have to hold the Infura API key. Unless we deliberately obfuscate, it could technically be searchable within the JS source inside the browser dev tools. Maybe it's not a big deal since we just get a free key.

2. Disabling the Manage tab could reduce explorability as I mentioned here: https://github.com/adrianmcli/emp-tools/issues/8#issuecomment-653026323