migrate from bower to yarn

[ppannuto]

From the build log:

Your project can stop working at any moment because its dependencies can change. Prevent this by migrating to Yarn: https://bower.io/blog/2017/how-to-migrate-away-from-bower/

[westbl]

Following the instructions at https://itnext.io/bower-to-yarn-migration-simple-steps-2a5ad0c43281 works, but the Highstock package can't be found by Yarn...not sure if it is possible to switch over without it.

[bradjc]

Do you happen to have a branch with your progress?

[westbl]

@bradjc here it is: https://github.com/um-cseg/chez-betty/tree/bower_to_yarn_test

[bradjc]

I can't find a replacement for bower-installer. I guess bower is terrible and old and whatever, but bower-installer works better than do-everything yarn.