update post create to accept whatsapp posts

[Mh-Asmi]

This pull request makes the following changes:

• add new column (contact_id) to posts table

• in posts creation for post of Whatsapp datasource :
  - I will check if there is a whatsapp contact for the passed phone number, if not I will create new one
  - use the id of the Whatsapp contact as value for contact_id column
  - set the source in post with value "whatsapp"
  - save contact info inside the metadata
  - set the author name with contact number, and author email null

• in getting posts

  • return the correct source of the post
  • return the contact number in the author realname
  • return the full contact object if the user is authorized users
  • return only contact_id of contact object for unauthorized users

• in filters

  • add Whatsapp to source filter
  • return the correct count of Whatsapp posts

Test checklist:

• [ ]

• I certify that I ran my checklist

Fixes ushahidi/platform# .

Ping @ushahidi/platform

[linear]

USH-1301 Update Post controllers to accept and return source & contact information

[tuxpiper]

Looks good 👍 I think I follow most of the changes.