Create PRIVACY_POLICY.md to keep consistency across all projects

### Is your feature request related to a problem? Please describe.
Register form on all AnitaB.Org Open source applications need to have common Privacy Policy. At the moment developers getting the content from https://anitab.org/privacy-policy/ and copy paste it to their code if they want to use a pop-up modal. This is prone to content manipulation or errors which makes code review difficult.

### Describe the solution you'd like
If we have PRIVACY_POLICY.md in the /documentation repo, developers can use .md parser in their project so that any changes made to this policy will automatically apply to that project. This ensures the policy is up to date and consistent across all AnitaB.Org Open Source projects.

### Describe alternatives you've considered
NA

### Additional context
I believe the content of the Privacy Policy of the AnitaB above can be used across all projects as indicated in the screenshot below.