Create How To Test doc

[critesjosh]

We have this testing page in the "Writing a DApp" tutorial, this testing page as a standalone tutorial and the "Testing" top level section.

We should combine these.

[critesjosh]

Testing should probably be a how-to rather than a tutorial

[critesjosh]

@catmcgee all of the pages I originally linked have moved. Do you think this issue is still relevant or should we close it?

[catmcgee]

@critesjosh still think this is a good thing to have so moving back to Planned

[critesjosh]

Since this back in Planned, do you have an estimate of when you will have capacity to work on this? I created more Iterations, so we can schedule issues for future weeks.

[catmcgee]

@critesjosh added iteration 37, could probably pick it up in 36. thanks for adding more iterations :)