Make testing for heroku appname duplication available when tyr is a library

[clarkerican]

Using tyr as a library runs into complications when the chosen name is duplicated or has uppercase/dashes. All the checks for the name should take place before the docker file is created so the docker file knows the correct herokuapp name. To solve this, we can make the function that validates the heroku app name available to the public.

[clarkerican]

Looked into this, it is not as easy as it sounds. The Heroku appname is validated during project creation on Heroku. The project creation on Endor may have to be refactored to account for this.
A couple options that I though of:

• Wait for all the files to be generated and the user waits while there is a spinner on the screen
• Bring the user to the project page, and when the files are ready, they can click a button to download them. (This may involve some sort of mechanism to indicate that the files are done.)