This change fixes both:
1. making multipart/form-data requests with content-type
header for every individual boundary
2. generating correct CURL command for multipart/form-data
request, allowing specifying content-type header for every
individual boundary
Refs #4826
Refs #5356
* config(jest): updated setup
* config(jest): update testMatch to include jsx files
* config(jest): add transformIgnorePatterns
* config(jest): update ignore files that do not work in jest yet
* config: add test:unit-jest to test script
* fix(jest): lint with eslint-plugin-jest
* refactor(jest): move unit test directory
* refactor(mocha): restore mocha tests that fail in jest
* docs(jest): update helpful scripts with test:unit-jest