Update the FHIRCore repo to add flavors

[dubdabasoduba]

Describe the solution you'd like

• Update the FHIRCore Android app to have flavors.
• This will help us config the App Icon and the App Name.

Solution

• Add and eCBIS and MWCore flavor for the project.
• Give the app_name & app_icon references on the manifest generic
  • use app_name for the name string
  • use app_launcher for the icon image names
• Update the strings.xml in each res folder for the 2 apps mentioned above.
  • Set the each of the names on the app_name
  • MOH eCBIS for eCBIS
  • Malawi Core for MWCore
• Add a new launcher icon on each flavor res folder. Remember to rename it to app_launcher for it to be used automatically.

[pld]

Updated title to note we want to be able to set the default App ID as well