Is there an existing issue for this?

• I have searched the existing issues

Is your feature request related to a problem?

There is an environment variable for the host that will give the absolute path to the project root directory. It would be great to have the equivalent in web so that we can use the variable in custom commands in the web container.

Describe your solution

Add DDEV_APPROOT="/var/www/html" to environment variables for the web service. (PR incoming)

Describe alternatives

The alternative is for the user to hard code that value in custom command files or create their own variable.

Additional context

No response