Add a Minion guide

[kraih]

We need a Minion guide explaining all the features with examples. And perhaps a cookbook explaining concepts that are combinations of features (notes and note searching for tagging jobs) or creative uses of features (such as rate limiting with locks).

[kraih]

The guide has been started and contributions would be very welcome. Every feature from the list needs a little section. 16c4d63...b310b43

[jberger]

I'll start a checklist here for remaining sections, please feel free to add and check off when complete:

• Job dependencies (parent/child)
• High priority fast lane