[RFE] Trousseau pre-flight check for gRPC unix socket presence on crash

[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?

a preflight check validating the presence of an existing unix socket file

-->Why do we want to build it?

• avoid manual deletion of the vault socket on the nodes
• improve unix socket reference from a k8s API server to avoir a API server crash

-->How do we want to design it?

dedicated process scouting the presence of an unix socket file and if it is used
maybe linked with #104