Add a method to the framework adapters interface to run async code before each test

[juliemr]

This will be used for things such as restarting the browser between tests. To avoid relying on control flow, we need to be able to run asynchronous things (like waiting for the new browser instance to start up).

This will look something like:

JasmineAdapter {
  addRunBeforeFunction(fn) {
    jasmine.beforeEach((done) => {
      fn().then(done);
    });
  }
}