UI Configuration Docs - Out of date

[tiffon]

trafficstars

Requirement - what kind of business use case are you trying to solve?

Help operators of Jaeger know how the UI can be configured

Problem - what in Jaeger blocks you from solving the requirement?

The UI configuration section of the docs are out of date.

Proposal - what do you suggest to solve the problem or improve the existing situation?

Update the docs to reflect how the UI can be configured.

Any open questions to address

[albertteoh]

Related issue: #489