tooling: Remove static/node_modules symlink.

It appears not to have been useful and makes it marginally harder to
reason about how module resolution works.  Paths to static content in
node_modules should be resolved through Webpack instead.

(This node_modules symlink was originally created in the pre-webpack world
where all of our static asset paths were based in static/.)

Signed-off-by: Anders Kaseorg <anders@zulipchat.com>

static/js/settings_account.js

@@ -312,7 +312,7 @@ exports.set_up = function () {
             if (page_params.development_environment) {
                 // Usually the Django templates handle this path stuff
                 // for us, but in this case we need to hardcode it.
-                zxcvbn_path = '/static/node_modules/zxcvbn/dist/zxcvbn.js';
+                zxcvbn_path = '/webpack/zxcvbn.js';
             }
             $.getScript(zxcvbn_path, function () {
                 $('#pw_strength .bar').removeClass("fade");

static/node_modules

@@ -1 +0,0 @@
-../node_modules/

zproject/settings.py

@@ -934,7 +934,7 @@ JS_SPECS = {
     # for bundling KaTeX.
     'katex': {
         'source_filenames': [
-            'node_modules/katex/dist/katex.js',
+            '../node_modules/katex/dist/katex.js',
         ],
         'output_filename': 'min/katex.js',
     },
@@ -943,7 +943,7 @@ JS_SPECS = {
     # good way to look up the path to the file).
     'zxcvbn': {
         'source_filenames': [
-            'node_modules/zxcvbn/dist/zxcvbn.js',
+            '../node_modules/zxcvbn/dist/zxcvbn.js',
         ],
         'output_filename': 'min/zxcvbn.js'
     },