protolint: configure protolint and fix the protolinting issues

This PR addresses the following:
- Install and Configure protolint to enforce the protobuf style guide rules in the CI.
- Fix the protolinting issues (package and import ordering) while maintaining the comaptibility.

lnrpc/devrpc/dev.proto

@@ -1,9 +1,9 @@
 syntax = "proto3";
 
-import "lightning.proto";
-
 package devrpc;
 
+import "lightning.proto";
+
 option go_package = "github.com/lightningnetwork/lnd/lnrpc/devrpc";
 
 /*