Auto upload feature

[csoni111]

Implements the auto/instant upload feature for images as soon as they are captured using camera. (#243)

Adds following things:

1. Upload Manager : For managing the uploads and processing upload queue one by one.

2. Upload Service : The background service which pushes urls of images to be uploaded to the sqlite db, initiates the upload manager and handle notifications for upload start, progress, success and error.

3. Upload Settings : The preference fragment which shows the UI for enabling/disabling auto upload and selecting the default upload HDA, Share and Path.

4. Camera Receiver : The Broadcast Receiver which listens for NEW_IMAGE broadcast sent by android device.

5. Upload Queue Db : The SQLite database for maintaining the upload queue in a persistent storage.

6. Upload Queue Db Helper : For accessing the SQLite database. Contains functions for CRUD operations on the db.

7. PhotosContentJob : Job to monitor for changes to photos in the media provider.

8. NetConnectivityJob : Job to start upload service on gaining network connectivity.

[csoni111]

The current approach followed for implementing the auto-upload feature is something like this:

On android 7 and above:
There are two jobs ->

• PhotosContentJob : It monitors content uri of image directory, and on any change, it starts a background service (UploadService) with image urls passed to the service which then adds those to the sqlite db, then checks if the device is connected to internet (also if the user has disabled "Allow on Cellular Data" in settings then checks for wifi connectivity), and starts the uploading process if connected.
  It is scheduled once using JobScheduler at the start of the application, then re-scheduled after every subsequent run of this job.

• NetConnectivityJob : It starts when the device is connected to the internet and starts the same service as above but without any image urls passed to it.
  It is also registered once at the start of the application. It is then re-scheduled from inside the UploadService, if it is detected that the network conditions are not met.

On below android 7:
Instead of the two jobs, there are two broadcast receivers ->

• NEW_PICTURE : It triggers whenever any image is captured on the device and does the same as done by PhotosContentJob.
• CONNECTIVITY_CHANGE : It triggers on any connectivity change in the device and starts UploadService if the network conditions are met for auto-upload.