* sort .gitignore and add apt_auth.conf to it
* add helper to setup.sh to create apt_auth.conf (user still needs to enter their own credentials)
* only create apt_auth.conf in make if it doesn't already exist
* add tooling to core dockerfile and makefile to use build secrets
* add ignore for hadolint as mounting syntax is currently not supported so far
* update to latest docker on travis for buildkit support
* documentation
* sort gitignore
* add dockerfile syntax definition for build args
* update to Debian Buster
* update webapp container
* update kdav image to buster
* add some debug commands
* use onbuild to specify building of core repository only in one place
* remove ca-certificates and git from kdav image
* git should not be needed since kdav has a builder stage
* ca-certificates is already installed in an earlier stage
* upgrade to Debian 10 for Z-Push
* switch remaining Debian 9 repos in webapp
* use a new major version for the base image
* since its now based on buster
* add new parameters to the onbuild step
* update repos in setup.sh
* switch default distribution in create repo script
* fixes for setup-tools.sh
fixes https://github.com/zokradonh/kopano-docker/issues/266
* add startup tests for meet demo
* add architecture to contributing file
* define ical_listen for kopano-ical
* precreate database if it does not yet exist
* fix spelling
* update supercronic to the latest release
* update tagging for base
* fix version tag for core
* put versions for all containers into labels instead
* define vcf_ref once
* remove cache-from as caches will be invalidated early on because of passing the git ref early on
* do not rebuild when publishing
* do not rebuild when publishing
* reduce layers required for env assignment
* pull newer base images for kdav, scheduler and ssl if available
* alsp publish tag for ldap containers
* fix publishing of ssl container
* remove surplus locale configuration (should only be in base image)
update konnect
add version to ldap and ldap_demo images
* also create a tag for the ldap images
* add ldap version to compose file
