feat(backup): add new check `backup_recovery_point_encrypted`

[danibarranqueroo]

Context

This new check ensures that AWS Backup recovery points are encrypted at rest. Encrypting recovery points provides an additional layer of protection against unauthorized access, safeguarding the confidentiality, integrity, and security of backup data. This practice ensures that backup data remains secure, even if accessed by unauthorized users.

As Moto does not cover most of the Backup service api calls, I needed to use Botocore for both tests.

Description

Added new check backup_recovery_point_encrypted with its unit tests.

Checklist

• Are there new checks included in this PR? Yes / No
  • If so, do we need to update permissions for the provider? Please review this carefully.
• [ ] Review if the code is being covered by tests.
• [ ] Review if code is being documented following this specification https://github.com/google/styleguide/blob/gh-pages/pyguide.md#38-comments-and-docstrings
• [ ] Review if backport is needed.

License

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 95.00000% with 2 lines in your changes missing coverage. Please review.

Project coverage is 89.67%. Comparing base (45c32ab) to head (49f89f3). Report is 1207 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5426      +/-   ##
==========================================
+ Coverage   89.21%   89.67%   +0.45%     
==========================================
  Files        1044     1078      +34     
  Lines       32225    33362    +1137     
==========================================
+ Hits        28750    29917    +1167     
+ Misses       3475     3445      -30     

Components	Coverage Δ
prowler	89.67% <95.00%> (+0.45%)	:arrow_up:
api	∅ <ø> (∅)