Add Gitlab CI configuration

This commit adds a .gitlab-ci.yml file, which uses a feature
to fetch the config from a centralized repository. The intent is
to have all the gstreamer modules use the same configuration.

The configuration is currently hosted at the gst-ci repository
under the gitlab/ci_template.yml path.

Part of gstreamer/gstreamer-project#29
8 jobs for alatiera/include-everywhere in 3 minutes and 49 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Manifest
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manifest

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  Build
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build fedora x86_64

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build fedora x86_64

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build fedora x86_64

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build fedora x86_64

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build fedora x86_64

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build fedora x86_64

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