Added MetadataService with GetHealth and GetVersion

[dutchie032]

Added an additional service. "MetadataService" for admin functionality that does not touch DCS itself.

GetHealth => for getting the gRPC server status
GetVersion => for getting the version of the cargo package.

Nothing too fancy, but can be handy for the client and verification.

Example requests:

[dutchie032]

Apologies for the manier protolint fix commits haha
Recommend possibly squashing commit anyway

[rurounijones]

Can we rename AdministrationtService to MetadataService or something that is VERY unlikely to ever have a name clash.

Administration is such a generic term that I could see it being useful in other contexts.

And yeah, a squash at the end will be good 😁

[dutchie032]

Updated the name to MetadataService. Chose AdministrationService due to it's administrative nature, but can imagine that indeed in the future there might be more "Administrator" type of services, so Metadata works for me

[rurounijones]

@dutchie032 Branch needs rebasing with merge conflicts, PR and README still says AdministrationService

[dutchie032]

@rurounijones conflicts resolved and namings fixed