[Feature Request] Changes in the documentation

### Request

Please do following changes in the documentation:

1. separate the references from the remaining documentation. It should have own group

2. add separate section with examples of each file, in with each would be:

- all existing in specification options
- for each option would be all possible values
- for options with multiple values, include the separator
- for each file to with it apply, put examples for both: local and remote references (for example in: `devcontainer.json` , features, templates, Dockerfile, etc.)

3. Group the documentation by (for example): topic category, etc. instead of leaving it mixed up

4. add navigation and search, with would allow to easier find required informations

### Explanation

Above proposals would make easier to create devcontainers