Global kwarg docs

• Adds a documentation ressource to the pages, under documentation -> Global Keywords
• ressource contains documentation of label, dfilter, flag mostly by showcasing examples
• to see rendered page, checkout the branch and build the doc locally.
• please only block the MR, if you feel basic principles/standards not reflected in the resource, or the language to be of inacceptable/incomprehensible level - additional examples and usage explainaitions can be part of own MRs to come. (so the bourden of documentation may be evenly distributed)