Disable wallet while no RPC connection is active

[HenkSwardt]

We need to look at disabling the wallet while no RPC connection is active. As discussed before, if the user is not aware of the fact that the connection has been lost, they might still want to do transactions but nothing will do on the back end.

The suggestion to prevent anything from being done until it re-establishes connection is to grey out the GUI in the case where connection is lost and inform the user of this. Maybe add a message to the left bottom corner like "Daemon connection lost, retrying connection"

[pciavald]

This will be done for 1.2 with the new IPC interaction / multiwallet / new modal flow. However we can already change the error messages for 1.1 @HenkSwardt @anandsinghparihar

[HenkSwardt]

Will change the current message for when daemon is not connected to the following.

"Daemon not connected, retrying connection"

[HenkSwardt]

Message update to be more info related than error related. Please see #598

[pciavald]

Info messages implemented. We still need to implement some behaviour when connection drops.

[zaSmilingIdiot]

Implemented as of v3.3.0

The application starts up to the main "home" view without first requiring that a connection to a particl-core node is established. The various modules/apps requiring a particl-core connection are disabled until such a connection is established, and navigation within such a module/app now reverts back to the "home" view if the connection to particl-core is dropped.