Update outdated domain references

[mertssmnoglu]

Issue - Outdated domain references

I noticed that some sections of the documentation still reference the old domain count.ly instead of the new one countly.com. This might cause confusion for users and lead them to outdated or inaccessible resources.

• countly-server/SECURITY.md

  Line 3 in 712c6ad

  Security is very important to us. If you discover any issue regarding security, please disclose the information responsibly by sending an email to [email protected] and not by creating a GitHub issue.

• countly-server/README.md

  Lines 108 to 113 in 712c6ad

  	## 👍 Badges
  	If you like Countly, why not use one of our badges and give a link back to us?
  	<a href="https://countly.com/?utm_source=badge" rel="nofollow"><img style="width:145px;height:60px" src="https://count.ly/badges/dark.svg?v2" alt="Countly - Product Analytics" /></a>

• countly-server/README.md

  Lines 56 to 60 in 712c6ad

  	* [List of Countly SDKs, documentation and download information](https://support.count.ly/hc/en-us/articles/360037236571-Downloading-and-Installing-SDKs)
  	* [SDK development guide to build your own SDK](https://support.count.ly/hc/en-us/articles/360037753291-SDK-development-guide)
  	* [Countly Server Write API to send data into Countly from any source](https://api.count.ly/reference/i)
  	## 🛠️ Installing and upgrading Countly server

Suggested Fix

• Search for all occurrences of count.ly in the repository.
• Replace them with countly.com to ensure consistency and accuracy across the documentation.

This update will improve user experience and prevent potential navigation issues.

[ar2rsawseen]

Hello
Thank you for pointing this out.
I have updated the readme in this PR: #5931

The email is used on the same old domain, so that part is not updated, as well as some graphics are linked to the old domain and will not be moved to new one, so I left them like this too :)