[tests-only] [full-ci] Change appInstallCommand to work with PHP unit tests

https://drone.owncloud.com/owncloud/contacts/977/3/3

7.3: Pulling from owncloudci/php
Digest: sha256:5c090434ce667b422b4258f9a24eeed2b390a8ca47f64b29b18917b492d061a2
Status: Image is up to date for owncloudci/php:7.3
+ cd /var/www/owncloud/server/apps/contacts
+ make npm
npm run build
Makefile:120: recipe for target 'npm' failed
make: npm: Command not found
make: *** [npm] Error 127

The app has both PHP and JavaScript dependencies. To install the PHP dependencies, the owncloudci/php image is needed. To install the JavaScript dependencies, the owncloudci/nodejs image is needed.

I have modified the drone starlark so that both "appInstallCommandPhp" and/or "appInstallCommandJavaScript" can be specified in the config section as needed. Each will be executed in the appropriate php or nodejs docker image, if specified.

This should work flexibly for other oC10 apps. I have copied the code back to https://github.com/owncloud/activity/pull/1007 so that that gets implement when we next update the oC10 app starlark across the apps.

owncloud / contacts

[tests-only] [full-ci] Change appInstallCommand to work with PHP unit tests #724