feat:add missing csp

[ilayda-cp]

Done

• Added missing csp that are used in the production

How to QA

• Go to HTTP header analyzer
• Verify CSP header isnt missing
• Go to https://snapcraft-io-4829.demos.haus/
• Verify all the images, videos, resources are shown correctly
• Verify there is no behavior change (such as a link doesnt open)

Testing

• [ ] This PR has tests
• [x ] No testing required (explain why): added security header

Issue / Card

Fixes #14413

Screenshots

[webteam-app]

Demo

Jenkins

demos.haus

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 85.33%. Comparing base (b8b6b55) to head (bec9f79). Report is 161 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #4829 +/- ## =========================================== + Coverage 66.80% 85.33% +18.53% =========================================== Files 113 102 -11 Lines 3714 7418 +3704 Branches 965 0 -965 =========================================== + Hits 2481 6330 +3849 + Misses 1098 1088 -10 + Partials 135 0 -135 ``` | [Files with missing lines](https://app.codecov.io/gh/canonical/snapcraft.io/pull/4829?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=canonical) | Coverage Δ | | |---|---|---| | [webapp/handlers.py](https://app.codecov.io/gh/canonical/snapcraft.io/pull/4829?src=pr&el=tree&filepath=webapp%2Fhandlers.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=canonical#diff-d2ViYXBwL2hhbmRsZXJzLnB5) | `88.66% <ø> (ø)` | | ... and [209 files with indirect coverage changes](https://app.codecov.io/gh/canonical/snapcraft.io/pull/4829/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=canonical)