add 'npm' and 'npm-update' make targets and lockfile (#7246)

* add 'npm' and 'npm-update' make targets and lockfile

- `make npm` installs and updates node_modules, triggered automatically
   on `make css` and `make js` as it completes reasonably fast and
   ensures consistent modules.
- `make npm-update` updates all dependencies to their latest version,
   regenerates `node_modules` from scratch and updates
   `package-lock.json`. It uses npm modules `updates` written by yours
   truly to find the latest version of each dependency.

* add suggested make dependencies

* remove package-lock.json during npm-update

* regenerate package-lock.json

.gitignore

@@ -67,7 +67,6 @@ coverage.all
 /node_modules
 /modules/indexer/issues/indexers
 routers/repo/authorized_keys
-/package-lock.json
 /yarn.lock
 
 # Snapcraft