External dialling

[richardolsson]

Description

This PR implements external dialling using the Telavox web interface and API. It allows a caller to click a number to trigger a call via Telavox if the user's person profile has telavox credentials in "magically" named custom fields telavox_username and telavox_password.

Screenshot

Note tab with Telavox dialling side by side with Zetkin tab.

Note to reviewer

To test this:

1. Create custom fields telavox_username and telavox_password, both of types text. Add valid Telavox credentials to the caller's profile via Zetkin Organize.
2. Create a call assignment, and importantly, only add targets with phone numbers you actually want to call. I tend to just replace all phone numbers in the dummydata with my own.
3. Open app.telavox.com in a separate tab and log in with the credentials. Run the tabs side by side
4. In Zetkin Call, click the number of a target to trigger a dial (for the first call, you might have to manually navigate to the Telavox tab and accept the call)

Related issues

Fixes #248

[niklasva82]

Great! It works and the code looks good. Only thing was that the "tutorial" still tells people to use the phone. This is minor but may cause confusion for first time callers with telavox?

[richardolsson]

Only thing was that the "tutorial" still tells people to use the phone. This is minor but may cause confusion for first time callers with telavox?

Great point! I've created a separate issue (#253) about this.