(core) freshen grist-core build

Summary:
 * adds a smoke test to grist-core
 * fixes a problem with highlight.js failing to load correctly
 * skips survey for default user
 * freshens docker build

Utility files in test/nbrowser are moved to core/test/nbrowser, so that gristUtils are available there. This increased the apparent size of the diff as "./" import paths needed replacing with "test/nbrowser/" paths. The utility files are untouched, except for the code to start a server - it now has a small grist-core specific conditional in it.

Test Plan: adds test

Reviewers: dsagal

Reviewed By: dsagal

Differential Revision: https://phab.getgrist.com/D2768

Dockerfile

@@ -6,7 +6,8 @@ FROM node:10 as builder
 
 # Install all node dependencies.
 ADD package.json package.json
-RUN npm i
+ADD yarn.lock yarn.lock
+RUN yarn install --frozen-lockfile
 
 # Build node code.
 ADD tsconfig.json tsconfig.json
@@ -14,7 +15,8 @@ ADD app app
 ADD stubs stubs
 ADD buildtools buildtools
 ADD static static
-RUN npm run build:prod
+ADD test/tsconfig.json test/tsconfig.json
+RUN yarn run build:prod
 
 # Install all python dependencies.
 ADD sandbox/requirements.txt requirements.txt
@@ -61,4 +63,4 @@ ENV GRIST_DATA_DIR=/persist/docs
 ENV GRIST_SESSION_COOKIE=grist_core
 ENV TYPEORM_DATABASE=/persist/home.sqlite3
 EXPOSE 8484
-CMD npm run start:prod
+CMD yarn run start:prod