Feat: remove Religion from the personal background attributes

### Is your feature request related to a problem? Please describe.
Having `Religion` as an attribute in the personal background can be intimidating to some users and might have negative impact in the mentors/mentees selection process if the organization has not fully embraced diversity and inclusion.

### Describe the solution you'd like
During [BIT Open Session May 16th 2021](https://docs.google.com/document/d/1vMmLOC8txyOZdNfdFh6keB5rw7uEbL1F6dS_JdcnD0g/edit#heading=h.rh3yl7l0u155), we've decided to remove `Religion` from being one of the attributes in user's personal background.

### Describe alternatives you've considered
NA

### Additional context
This issue will be addressed once #1092 is merged to `bit` branch.