Workbench mode: Warn about implausible timestamps

[amotl]

Hi there,

@Tonkenfo shared an idea about a feature which could be enabled by toggling a "workbench mode".

It would be sweet if Kotori could indicate somehow if the timestamp received on individual acquisition channels deviates too much from the current time. Mostly, this indicates that the client timestamp is wrong.

With kind regards,
Andreas.

[amotl]

Kotori can also do bulk- and backfill-imports. In such scenarios, timestamps in the past are also plausible. That's the reason a user would only want to enable such a feature on demand, and on individual channels.