[ENHANCEMENT] What if keychain can't contact ANY nodes?

[forkyishere]

This one will be useful for "pro-users" mostly but also allow for some situations in which users have difficulties, and then this would allow them to understand (choose) more.

Use Case: When there is no good network or the selected RPC node is not responding, the keychain defaults to not allowing access to the wallet. Changing access to the current wallet cache, even without access to the RPC nodes, will be a "life improvement" for most pro users. Will also teach most users to understand that your stuff is still there... and you can still add/remove them without interaction with the blockchain.

Proposed Changes:

• Allow access to the wallet keys and (bonus) cached information (dating last updated version).
• Allow management of keys (one should be able to add/remove them).
• (optional) misc customization already available like selecting other HE and HIVE nodes but not just for published nodes (aka custom added nodes) with priorities (or an attribute to select them, like ping, RPC call latency, etc)

I had this one mostly when I had problems with my active selected RPC nodes, but it will be something that will improve/teach experience with blockchain when "there is no communication" with the internet.

I am probably missing other cases, but these are the most I have been crossed with.

[stoodkev]

Yeah that's sth we want to tackle at some point. That would need quite a big refactor though, so it will probably take some time.