show new classes and attributes with different color

[VladimirAlexiev]

At https://semiceu.github.io/MLDCAT-AP/releases/1.0.0/html/overview.jpg,
show the new (OML) classes and attributes with different color. This is important for 2 cases:

• to review the new OML terms
• to facilitate understanding of the OML terms (assume that the reader has DCAT in-depth, and just needs to study the new terms)