[add-resource] New Plugin/Theme : Uptime monitoring

[DennisdeBest]

I would like to add my new plugin/theme to the Grav Repository.
Here are the project details: DennisdeBest/grav-plugin-uptime

There is already a healthcheck plugin but I wanted to add some data and make it easier to add data coming from the env variables.
So I created a new pretty simple one.

Here it is on my website https://debest.fr/uptime running on self hosted Dokploy.

Happy to hear if it is OK or if changes are required.

Thanks !