Allow CSS properties on bleach.clean

[diwash007]

Description

Currently, the CSS attributes are being cleaned by the bleach.clean method. This Pull Request adds support to allow CSS properties on the pages instead of removing them.

Fixes #530

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

By creating blog post with different image alignments

Checklist:

• My code follows the style guidelines of this project
• I have not added a commit to any .db files as part of my pull request
• I have performed a self-review of my own code
• I have commented on my code, particularly in hard-to-understand areas
• My changes generate no new warnings
• Any dependent changes have been merged and published in downstream modules

[diwash007]

Hi @botanicvelious, May you please review this Pull Request
also, #534