[Fleet] Generate unique ID by stream

[nchaulet]

Description

Should resolve elastic/beats#22054 (comment)

We should generate a unique ID for each stream.

This ID could be of the form ${input.type}-${packageStream.data_stream.dataset}-${input.id} and will be saved when the package policy saved object is persisted.

[elasticmachine]

Pinging @elastic/ingest-management (Team:Ingest Management)

[ruflin]

I remember we were thinking about using this id also for debug purpose in the future. So having some human readability as part of it would be beneficial.

[ph]

Seems to be related to the observability goals?

[nchaulet]

@ph yes it's related to observability having correct ids for stream and inputs there is also this issue to fix for input id #82426