implement validation of "related business cases" and "Reference to mentioned use case objectives"

[VladimirAlexiev]

https://smart-grid-use-cases.github.io/docs/usecases/bridge/edf-1/#13-scope-and-objectives-of-use-case mentions "Related business case(s)": 01314521-bbb8-496a-b55b-8405057935eb. This GUID is not found anywhere on the web.

• According to excel comment, this field should be "Comma separated list of related use cases".
• Please define the required format, and implement validation that it refers to a valid use case identifier (eg bridge/edf-2).
• The validation should result in warning not error, since that related case may be added after the case that has the relation

[VladimirAlexiev]

• https://smart-grid-use-cases.github.io/docs/usecases/bridge/edf-1/#15-key-performance-indicatiors-kpi also includes in "Reference to mentioned use case objectives" some GUIDs that are nowhere to be found, eg 95bbcb38-254b-48b6-aa52-027fd4b1b50e .
• https://smart-grid-use-cases.github.io/docs/usecases/bridge/edf-1/#17-further-information-to-the-use-case-for-classificationmapping also includes "Relation to other use cases": SUC. Presumably this means "System Use Case", but the purpose of this field is to link to another use case
• After validation: please render the relations as HTML links.