Field dependency viewer/analyzer

[jguay]

Describe the feature:

• Field analyzer application would allow to see for a given index and field names which visualizations/saved searches/ML jobs/Transform jobs may be affected if the field is removed or changed
• Also such tool should parse elasticsearch transform/ML job/datafeed make use of the field(s)
• Support for Cross Cluster Search indices as well

Describe a specific use case for the feature:

• When a field is removed from an index or a new data stream is created with a different datatype for the field, this may cause issues for saved searches, visualizations and dashboard which may need to be corrected by the owner/maintainer of affected objects
• Also the impact may not be limited to kibana saved object transform or ML or watcher job using that field may stop working

[elasticmachine]

Pinging @elastic/ml-ui (:ml)