Simplified the parameters.yml file

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | -
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

Originally, the `parameters.yml` was designed to define the infrastructure-related settings (in other words, the settings that may change from one computer to another). Meanwhile, the `config_*.yml` files are the ones that define the application behavior (in other words, the settings that stay the same from one computer to another).

In my opinion, the three removed parameters are related to application behavior and they shouldn't be defined at the `parameters.yml` file.


given that this setting impacts the routing definitions and the asset url, it would be better to avoid depending on the debug mode but only on the environment. The cached router is not varying based on the debug flag, so accessing the same environment in debug mode and in non-debug mode could create weird issues if the assetic config is based on it.

It is better to define either ``true`` or ``false`` in ``config_dev.yaml`` rather than ``%kernel.debug%``