Proto commits in Nitrokey/nethsm

These 3 commits are when the Protocol Buffers files have changed:

Commit:fde7334
Author:Sven Anderson
Committer:Sven Anderson

Vendor protoc-plugin into etcd-client

The documentation is generated from this commit.

Commit:0730aa8
Author:Sven Anderson

Truncated history

Commit:51b17ad
Author:Sven Anderson
Committer:Sven Anderson

etcd_store: implement gRPC client Signed-off-by: Sven Anderson <sven@anderson.de>