[BUSINESS TERMS] Make a "Definition" field as a rich text with possibility to use referernces to Terms

[RamanDamayeu]

• During Terms creation use reference to Terms
• During modification of definitions use reference to Terms
• Add view Term (that shows what terms are assigned to the current Term)

[Vladysl]

implemented in https://github.com/opendatadiscovery/odd-platform/pull/1668