Contributing update links (#1200)

* Update contact email for reporting CoC incidents

Update outdated contact email for reporting Code of Conduct incidents

* Revise contribution guidelines and add Slack info

Updated the contribution guidelines to include a link to the documentation and added information about the project's Slack channel.

* Update CONTRIBUTING.md

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>
Signed-off-by: Sam Stepanyan <[email protected]>

---------

Signed-off-by: Sam Stepanyan <[email protected]>
Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

Author: securestep9

CONTRIBUTING.md

@@ -1,3 +1,5 @@
 Developers
 ==========
-Hello, if anyone interested to contribute OWASP Nettacker Project, we gladly support and appreciate that! Please take a look at [Developers Document](https://github.com/OWASP/Nettacker/wiki/Developers) on wiki page and let me know if you have more questions.
+Hello, if anyone is interested in contributing to the OWASP Nettacker Project, we gladly welcome you! See the [Developers Document](https://nettacker.readthedocs.io/en/latest/Developers) in our documentation.
+
+If you have any further questions you can use the project's Slack channel: [#project-nettacker](https://owasp.slack.com/archives/CQZGG24FQ) on [OWASP Slack](https://owasp.slack.com)