Onboarding: add medications page

[rrabinovitch]

As a user in the process of registering,
After I've entered my profile details and I click "next",
I am redirected to a medication search page where I see instructions that prompt me to add medications to my profile, a medication search field, a "search" button, and a "skip for now" button.

Implementation details:

• figure out what route is used for this view
• compose the search instructions, including specifying that user should search for a med by its brand name not its generic name

[ejdelsztejn]

Route could be /medications/search and we could have a Medications::SearchController.