Color log markers by user-specified log fields

[SOF3]

Which problem is this PR solving?

• Resolves [Feature]: Colormap log markers by tag #2361

Description of the changes

• Add a settings dialog to TracePage
• Add an option to select log marker color keys
• Change log marker colors from black to colorgenerator-based (same color generator as span bars, but with only 2/3 brightness to avoid producing identical colors)

How was this change tested?

(This is my first time working with a reactjs project, would appreciate pointers to what tests I need to write)

Checklist

• I have read https://github.com/jaegertracing/jaeger/blob/master/CONTRIBUTING_GUIDELINES.md
• I have signed all commits
• I have added unit tests for the new functionality
• I have run lint and test steps successfully
  • for jaeger: make lint test
  • for jaeger-ui: yarn lint and yarn test

[yurishkuro]

what is the meaning of multiple colors on the same tick?

[yurishkuro]

These don't seem relevant in any way to the "page header" type. Is it possible to use the Context API to keep the knowledge of the settings only to the components that actually need this knowledge, such as the Settings popup and the SpanBar that renders the ticks?