Create a setting page for the Lunch App

[Muffles]

Context
The slack integration and API have hardcoded coordinates and number of results to get from Zomato

Issues

• Once we release this to the public, the users wont be able to use the App based on their location
• Each user may want to define a number of results to get from Zomato

Tasks

• Figure out how to have a settings page for the Lunch app in the Slack Apps page
• Add an option (input field) to define the number of results to get from Zomato. Default to 5
• Add an option (button) to trigger the google maps API and get the current coordinates of the user