Add FAQ

[dlhaines]

It would be good to add an FAQ to deal with a couple of questions dealing with using Anaconda.

• How should Anaconda-navigator and specific application be updated?
  The little gear at the upper right of an application tile has an option to update.
• How can specific packages in an environment be updated? E.G. this may be required because of an application update. It should be infrequent.
  Click on the environment tab on the left of the navigator, select the environment to update and select the packages to update.