Download provider list to local repo

Currently, the encounter provider list is hard coded to the muzima forms. It has created challenges of constant updating of the provider list.

Suggested options:

• Periodically synchronize the entire provider list to local repo. Under setting, it has option of "default encounter provider" which logged-in user as default encounter form provider. When this option is enabled, it should hide the encounter provider field on the encounter form. When this option is disabled, it allows users to search from the entire provider list.
• Another option is to adopt similar workflow how to parse concepts from form templates and also options to add more provider on demand which should be options in the initial wizard and also under setting - similar to add more concepts workflow.

As a user on the device side, I want to download the latest provider list to the device so that I can set my default encounter provider for all form templates.

Acceptance Criteria: User can download latest provider list to device.