Resolve "notices wont throw in *-debug* images"

Closes #3

See merge request !4

moved xdebug to stable for php-7.3

renamed debug-baseimages

added support for php 7.3

See merge request !3

* updated base-image to alpine3.8
* removed duplicate `intl`

Merge branch '2-klonen-von-nicht-oeffentlichen-gitlab-repositories-durch-composer-container' into 'master'

Resolve "Klonen von nicht-öffentlichen Gitlab-Repositories  durch Composer-Container"

Closes #2

See merge request !1

Resolve "world-readable for httpd"

Closes #1

See merge request !2

added cache-folders as external volumes to debug-variant

uids in dev-envs
removed message für setting uid and gid
added first tests

removed www-data homedir from chown process in entrypoint-script