Add programming resources for Django, Deno, and Docker

[connectwithvanshika]

Added new verified learning resources for Django, Deno, and Docker.

What does this PR do?
Add resource(s)

Description
This pull request adds free and verified resources for three technologies — Django, Deno, and Docker — enhancing the repository’s web development section with comprehensive tutorials and official documentation.

Added Resources:
Django: Official Documentation, Django Girls Tutorial, Full Stack Python, and MDN Web Docs Tutorial.
Deno: Official Manual, Comprehensive Introduction, and The Deno Handbook.
Docker: Official Documentation, Docker Curriculum, Play with Docker Classroom, and FreeCodeCamp Node.js App Tutorial.
Why is this valuable?
Expands the repo with trusted and well-structured learning materials.
Supports beginners and intermediate developers with practical guides.
Ensures all sources are free, educational, and verified.
How do we know it's really free?
All listed resources are official, open-access documentation or community tutorials that are publicly available without paywalls.

Checklist:
[✅] Searched for duplicates.
[✅] Included author(s) and platform where appropriate.
[✅] Put lists in alphabetical order and correct spacing.
[✅] Used an informative name for this pull request.
[✅] Ensured proper markdown formatting and consistency.
Follow-up
Check GitHub Actions for any reported warnings after submission.

[github-actions]

Linter failed, fix the error(s):

free-programming-books/books/free-programming-books-langs.md
 691:1-695:120  warning  Incorrect number of blank lines between last section and next heading  blank-lines-1-0-2      remark-lint
   699:1-702:2  warning  Incorrect number of blank lines between last section and next heading  blank-lines-1-0-2      remark-lint
   705:1-710:2  warning  Alphabetical ordering: swap l.706 and l.705                            alphabetize-lists      remark-lint
   705:1-710:2  warning  Incorrect number of blank lines between last section and next heading  blank-lines-1-0-2      remark-lint
 713:1-716:140  warning  Alphabetical ordering: swap l.714 and l.713                            alphabetize-lists      remark-lint
 713:1-716:140  warning  Alphabetical ordering: swap l.716 and l.715                            alphabetize-lists      remark-lint
  713:3-713:60  warning  Remove trailing slash (https://docs.docker.com)                        no-url-trailing-slash  remark-lint
  714:3-714:54  warning  Remove trailing slash (https://docker-curriculum.com)                  no-url-trailing-slash  remark-lint
  715:3-715:71  warning  Remove trailing slash (https://training.play-with-docker.com)          no-url-trailing-slash  remark-lint
2137:1-2137:12  warning  Do not use headings with similar content (703:1)                       no-duplicate-headings  remark-lint
2671:1-2671:10  warning  Do not use headings with similar content (697:1)                       no-duplicate-headings  remark-lint