Feature/pages encryption

[brij-mandaliya]

Fixes Issue : Encrypted Pages

closes #41

Changes proposed

• Add Encrypt-Decrypt Functionality for pages
• Also if page is encrypt and user or admin want to edit that page then they have to required the password for edit the page
• Also if user or admin want to view the page content then they can enter password and view the page content
• Also if they export the page then they required the password For Export

Check List (Check all the applicable boxes)

• My code follows the code style of this project.
• My change requires changes to the documentation.
• I have updated the documentation accordingly.
• All new and existing tests passed.
• This PR does not contain plagiarized content.
• The title of my pull request is a short description of the requested changes.

Screenshots

Note to reviewers