[RFE] KMS provider code to be running as a sidecars

[romdalf]

Is it linked to a user story? (use the "#" to tag the user story)

#50 - Result of Design meeting held on June 9th 2022 with @cvlc @mhmxs @vfiftyfive @rovandep

What do we want to build?

Dynamic KMS Plugin attachment using a sidecar approach.

Why do we want to build it?

Provide flexibility to introduce new KMS providers even with a running instance of Trousseau.

How do we want to design it?

Decoupled Trousseau's KMS provider code into separate independent binary to run as a sidecar.
Each KMS provider sidecar will have its own dedicated unix socket file.

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