Identify and lock current location for add plant

[Jagdeep1]

• Drop a pin for current location - Whenever map loads drop a pin at the current location
• Don't allow the user to change location while adding a plant, add plant only for the current location. This is to avoid junk data

[itachiRedhair]

Done: Locked with the current location fetched at the launch of app. Remaining: Fetching user location again when add plant is clicked.