deps: move inspector_protocol to deps

Dependencies that influence directly what goes into the `node` binary
should be in `deps/`.

Refs: nodejs#21975 (comment)

Author: addaleax

LICENSE

@@ -1035,7 +1035,7 @@ The externally maintained libraries used by Node.js are:
     OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   """
 
-- inspector_protocol, located at tools/inspector_protocol, is licensed as follows:
+- inspector_protocol, located at deps/inspector_protocol, is licensed as follows:
   """
     // Copyright 2016 The Chromium Authors. All rights reserved.
     //