[FEATURE] Add "Apply policy" action on data streams page

[spapadop]

Is your feature request related to a problem?
There is no easy way to apply a policy to an already created data stream.

What solution would you like?
While on data streams page, be able to select my data stream, click on "Actions" and have a new "Apply policy" item there. The expectation is that it applies it on all the internal indexes of the data stream.

What alternatives have you considered?
Go to Indexes page, toggle "Show data stream indexes", click on "Data streams", select my data stream, select all the internal indexes of my data stream, click on "Actions" and "Apply policy".

Do you have any additional context?

[dblock]

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