feat: add csp header configuration for review

[saurabh2590]

Description

• Adding CSP Headers configuration for bettermarks proxied domains.

Links to Tickets or other pull requests

OPS-6579

Changes

Datasecurity

Deployment

New Repos, NPM pakages or vendor scripts

Screenshots of UI changes

Approval for review

• All points were discussed with the ticket creator, support-team or product owner. The code upholds all quality guidelines from the PR-template.

Notice: Please remove the WIP label if the PR is ready to review, otherwise nobody will review it.

[saurabh2590]

Intent:
Here, we want to add the following config:
This is an example of Brandenburg should be similar to Niedersachsen, too.
Staging:

add_header 'Content-Security-Policy-Report-Only' "default-src 'self' 'unsafe-eval' 'unsafe-inline' *.bettermarks.staging.brandenburg.dbildungscloud.org *.staging.brandenburg.dbildungscloud.org; report-uri https://csp-report.bettermarks.staging.brandenburg.dbildungscloud.org/csp/report-only";

Production:

add_header 'Content-Security-Policy-Report-Only' "default-src 'self' 'unsafe-eval' 'unsafe-inline' *.bettermarks.brandenburg.cloud *.brandenburg.cloud; report-uri https://csp-report.brandenburg.cloud/csp/report-only";