Allow sites to specify PHP version

[brandonkelly]

Each site should be able to specify their own PHP version via a php property under sites in the config, and Nitro should auto-install the required versions if they don’t exist.

sites:
 - hostname: example.test
   webroot: /nitro/sites/example.test/web
   php: "7.2"

[lukeholder]

Just an idea if this goes ahead, the machine should probably have a setting for the default CLI PHP version. or ability to change the CLI PHP version in use which ssh'd into the machine.

[jasonmccallister]

Sites are now PHP version specific as well as enabling xdebug per site. Please see the documentation here for upgrading instructions https://craftcms.com/docs/nitro/2.x

[bencroker]

Jason you champ, thanks for making Nitro 2 so so good!!