Extend URI links to specify the type / term of the linked resource

[nilshoffmann]

Currently, arbitrary resources can be linked to from mzTab-M already. However, for machine readability and interpretability, defining the (cv-controlled) type, at least optionally, would simplify interpretation of the cross-linked information / resource. Additionally, the links could specify to which part / entity in mzTab-M they refer to, if that applies, if no more specific mechanism exists.

[nilshoffmann]

https://github.com/HUPO-PSI/mzTab/blob/master/specification_document-releases/2_0-Metabolomics-Release/mzTab_format_specification_2_0-M_release.adoc#6216-uri1-n

https://github.com/HUPO-PSI/mzTab/blob/master/specification_document-releases/2_0-Metabolomics-Release/mzTab_format_specification_2_0-M_release.adoc#6216-uri1-n