Display modal when waiting for location

[jgibson02]

Description:

When the app is opened, the Android location provider usually needs to wait for some time while it acquires a high-accuracy fix. During this time, it is currently not apparent to the user why their location is not shown or why their device does not appear on the client app.
To make it more apparent to the user what is happening, a loading modal should appear over the rest of the interface while the location provider is waiting.

Steps To Reproduce:

Workaround:

Risks:

TBD

Acceptance Criteria:

• User is presented with a loading modal when the app is open and the location provider does not have a location fix
• The loading modal is hidden once a location fix is acquired.