[ML] Url generator

[alvarezmelissa87]

Create a url generator that can be used in all the places in the ML plugin where URLs are being created in place or in scattered helper functions so that there is a central place where all that logic is being done.

This Url generator can also then be used by other plugins when they need to create ml URLs.

For example, something similar to the dashboard URL generator (src/plugins/dashboard/public/url_generator.ts) or jobs/components/custom_url_editor/utils.js
should work.

It should provide a solution for kibana issues open for this sort of URL generator functionality like:
#61785
#42845

[elasticmachine]

Pinging @elastic/ml-ui (:ml)

[streamich]

I more recent example would be Discover URL generator, take a look at that.

https://github.com/elastic/kibana/blob/master/src/plugins/discover/public/url_generator.ts

[peteharverson]

A URL generator has been added for 7.9.0 for the Anomaly Explorer in #71082. This needs to be enhanced to generate URLs for the other ML pages, including:

• Single Metric Viewer
• Anomaly Detection Job Management page
• Data Frame Analytics Job Management page
• Data Visualizer

[peteharverson]

Closing as fixed by enhancements to MlUrlGenerator to extend to all ML pages for 7.10 in #75696.