Merge relevant changes form branch gitlab_ci_setup_production to enable gitlab ci pipeline

GitLab CI pipeline is now ready to be merged into branch master. There are three jobs for building Jekyll pages, creating GitLab pages (since the page is not yet online) and triggering team-map project. The last job is commented out for later usage.

_data/team.yml

+- name: "John Doe"
+  city: "Heidelberg"
+  country: "Germany"
+  address: "Im Neuenheimer Feld 280"
+  organization: "dkfz"
+  twitter: "johndoe"
+  gitlab: "johndoe"
+  github: "johndoe"
+  mail: "john.doe@dkfz.de"
+  picture:
+- name: "Jane Doe"
+  city: "Dresden"
+  country: "Germany"
+  address: "Bautzner Landstr. 400"
+  organization: "hzdr"
+  twitter: "janedoe"
+  gitlab: "janedoe"
+  github: "janedoe"
+  mail: "jane.doe@hzdr.de"
+  picture:
+- name: "Foo Bar"
+  city: "Dresden"
+  country: "Germany"
+  address: "Bautzner Landstr. 400"
+  organization: "hzdr"
+  twitter: "foobar"
+  gitlab: "foobar"
+  github: "foobar"
+  picture:
+  mail: "foo.bar@hzdr.de"
+- name: "Erika Mustermann"
+  city: "Potsdam"
+  country: "Germany"
+  address: "Telegrafenberg"
+  organization: "gfz"
+  twitter: "erika"
+  gitlab: "erika"
+  github: "erika"
+  picture:
+  mail: "e.mustermann@gfz.de"
+- name: "Max Mustermann"
+  city: "Leipzig"
+  country: "Germany"
+  address: "Permoserstr. 15"
+  organization: "ufz"
+  twitter: "max"
+  gitlab: "max"
+  github: "max"
+  picture:
+  mail: "m.mustermann@ufz.de"
+- name: "Hans Meier"
+  city: "Braunschweig"
+  country: "Germany"
+  address: "Lilienthalplatz 7"
+  organization: "dlr"
+  twitter: "meier"
+  gitlab: "meier"
+  github: "meier"
+  picture:
+  mail: "hans.meier@dlr.de"