Update/Improve Documentation in Wiki

[Robert-W]

Do you want to request a feature, improve documentation, or ask a question?

Improve Documentation. We have merged many PR's that have added new features, changed configurations, etc. We should update the wiki to include all these additions.

TODO:

• [x] Review merged PR's and add items to the list below.

Things to add to the wiki:

• [x] #108 Improve auth documentation, provide examples
• [ ] #118 Give example of adding errorHandler and requestHandler middleware
• [x] #111 Document custom operations and how to use them, provide an example
• [x] Update documentation for "Getting Started" section, including example request to a resource
• [x] Update contributors guide
• [x] Update Metadata documentation since we support custom metadata hooks

If there are other things we are missing documentation on, please comment below and we will add those as soon as we can.

[dominathan]

I'd add a doc for how to add custom operations

[Robert-W]

I'd add a doc for how to add custom operations

Added to list, thanks

[joepaquette]

In ConfiguringProfiles.md, the "Go to src/constants.js to find a list of all supported profiles with their associated keys." comment is not correct. The supported profiles/keys do not exist in the src/constants.js.