We used to depend fully on Djblets's djblets/dependencies.py for the

list of Node.js packages to install, since we just made use of the basic

static media tooling in Djblets.
This change makes Review Board's package.json a primary source of

dependencies. Right now, we just depend on Djblets (via the .djblets

symlink set up when setting up a development environment), setting it up

as a Node workspace to make full use of symlinks. Upcoming changes will

move more dependencies into this.
This package.json lives in reviewboard/, making it available to

consumers of published packages. We then symlnk to the root of the tree.
These dependencies are reflected into reviewboard/dependencies.py via

a new script that is run any time we run npm install --save or

npm uninstall --save (if that operation would update node_modules).
This way, it should be easier to ensure that we have the right

dependencies in the tree for building static media, looking up types, or

linting the files.

Erased node_modules and re-ran setup.py develop. Verified I got a

working tree, which I was able to use to compile a new package, and

could use with upcoming changes that make deeper use of these

dependencies.
Ran npm install --save ... and uninstall --save ... and verified

that reviewboard/dependencies.py was updated.