[1] White Screen of Death due to User System Clock not being Synchronized

**Describe the bug**
A user has reported getting the white screen of death (WSOD) because his clock time was not synchronized with standard time (approximately 5 minutes of difference). This occurred when starting the reference wallet. No indication about the problem was indicated except through the debug log.

**To Reproduce**
Steps to reproduce the behavior:
1. Perturb system clock from standard time by 5 minutes
2. Start reference wallet
3. See white screen of death

**Expected behavior**
The user should be notified that his clock is off and that it requires synchronization.

Alternatively, if the user's clock is synchronized within some tolerance but the problem is with the clock of the connected node (#1228, #1826, #2091) then the user should be notified of this problem and be offered an opportunity to select another node.

**Screenshots**
The user provided a screen shot of the logs that contained the following message:

> willTransitionTo err: Error: Chainstore sync error, please check your system clock


**Desktop:**
- Downloadable Reference Wallet
- Version BitShares 2.0.190410-rc1

**Web Wallet
The same behavior was reported by the user when accessing the web wallet that was present at wallet.bitshares.org

**Additional context**
The behavior was resolved after the user synchronized his system clock to standard time

Start by reproducing the clock-offset condition in the downloadable reference wallet and web wallet, then trace the logged “Chainstore sync error, please check your system clock” path. Done means the user is notified when the local clock or connected node clock is out of tolerance and can select another node when appropriate.

Written by the indexing model from the issue text.