Serverless - We need to operate without any server

[juanky201271]

We have a long list of servers to use and the App change automatically the current server in case of error, but We still need to operate with NO server.

The App have to start and read the current wallet file with no server, also be able to show the seed/birthday, the transactions, etc... from the last time the wallet was connected to a server.

CC: @zancas @Edicksonjga

[juanky201271]

I need something like: LightClient::read_wallet_from_buffer_runtime but without specifying the server... in zingoconfig::load_clientconfig. This is the first step to implement serverless zingo-mobile.
@zancas @Oscar-Pepper @AloeareV @dorianvp

[juanky201271]

Some ideas:

1. Change settings to include another type of server selection besides auto, list, custom. Can be serverless or no server.
2. Change the first screen where you can set a custom server and add here the option for serverless or no server.
3. And maybe another side menu option for this to help to the user to switch to serverless or no server faster,