For each hint allow hint reveal delay based on seconds

[javajon]

There is currently a fixed 3-second delay on each hint. (in SubcommandRequestHint.java, taskUptime > 3). Typically the 3 seconds is shorter than when the learner reveals the hint. In the next version, it with be an optional adjustment by the author, set to a short default, perhaps 0,1, or 2 based on testing. A slight delay of ~1 second rather than 0, may still be wanted more for performance reasons.

1. Overall there will be a global delay setting defaulted to 0, this global default setting may be adjusted by the author.
2. In the markdown for each hint, there will be an optional time delay.

Units are in seconds.

Overall time delays are not encouraged as time is very subjective based on each learner's speed, distractions, hardware, skills, and accessibility.

These details will be added to the challenge documentation.