service: plumb contexts to all (most) threads (#7363)

This continues the push of plumbing contexts through tendermint. I
attempted to find all goroutines in the production code (non-test) and
made sure that these threads would exit when their contexts were
canceled, and I believe this PR does that.

light/proxy/proxy.go

@@ -57,6 +57,7 @@ func (p *Proxy) ListenAndServe(ctx context.Context) error {
 	p.Listener = listener
 
 	return rpcserver.Serve(
+		ctx,
 		listener,
 		mux,
 		p.Logger,
@@ -75,6 +76,7 @@ func (p *Proxy) ListenAndServeTLS(ctx context.Context, certFile, keyFile string)
 	p.Listener = listener
 
 	return rpcserver.ServeTLS(
+		ctx,
 		listener,
 		mux,
 		certFile,