kubernetes/kubernetes#132216

Various libraries kill Go's ability to do dead code elimination.

Follpwing these techniques I got pilot-agent from 25.7mb to 20.9mb! This required disabling text/template, -tags=grpcnotrace, and removing an import on github.com/grpc-ecosystem/go-grpc-middleware/retry which imports the net/trace.

• grpcnotrace is just valid
• grpc-go-middleware can probably get a patch upstream to respect grpcnotrace
• Replacing text/template is more problematic since we use it for the bootstrap. need to find a solution for that!