Add template for Plausible

### Application Name

Plausible

### Describe the application

Simple, open source, lightweight and privacy-friendly web analytics alternative to Google Analytics.

### URL to the application

https://plausible.io/

### Source code

https://github.com/plausible/analytics

### Application Icon

https://avatars.githubusercontent.com/u/54802774

### Link to Docker compose

https://github.com/plausible/community-edition/blob/v3.0.1/compose.yml

### Maintainer

- [ ] I am the maintainer

Start with Plausible’s referenced community-edition compose.yml and compare it with existing Kubero application templates. Add the Plausible template using the repository’s established template structure; done means Plausible is represented as an available application with its deployment configuration.

Written by the indexing model from the issue text.