Feat: Refactor is_public boolean to visibility enum on personal background

[mtreacy002]

Is your feature request related to a problem? Please describe.

The current is_public attribute limits users in their options in relation to their personal background.

Describe the solution you'd like

as per discussed on BIT Open Session:

• is_public should be refactored from a boolean type and renamed visibility which provides options for users to opt their personal background to be:
  • visible to all users
  • visible to organizations only
  • visible to BIT only

Describe alternatives you've considered

NA

Additional context

This issue will be addressed once #1092 is merged to bit branch

[mtreacy002]

Self-assigning as this is an action item discussed on BIT Open Session May 16th 2021