Add support for endpoints used in mobile app

[arpith]

From https://github.com/zulip/zulip-mobile/blob/master/src/api/apiClient.js, the endpoints used in the React Native mobile app that are not yet here are:

• /get_auth_backends
• /dev_get_emails
• /dev_fetch_api_key
• /users/me/presence
• /messages/flags

[erandiganepola]

Is this issue fixed?
If not may I implement this?

[arpith]

hey @erandiganepola! your contribution would be super welcome 😄 take a look at https://zulip.readthedocs.io/en/latest/git-guide.html etc to see how to go about contributing

[erandiganepola]

Thank you, I will look into that 👍