Openruko business process to register addon

Documentation here https://github.com/azukiapp/apiserver/wiki/Openruko-Addons
By default, when you register an addon, test plan is created and the addon is
available as 'beta' version.

List all available add-ons

GET /addons

Defining price as object on addon list

Removing heroku_addons view

Openruko business process to register addon

Renaming oraddon to addon