Persist: Develop DB schema for order-list

[afalenski]

A mongoose schema has to be developed to store the order-list in the mongodb.

To think about: How to store the data in the most efficient and secure way. Perhaps read best practices docs for mongo-db.

Dev-Note:

• Add the new schema to master-data and server repos

[afalenski]

Hey team! Please add your planning poker estimate with ZenHub @bfrgottscma @GerberI @ruegenbfr

[afalenski]

Please add your planning poker estimate with ZenHub @birgitlewicki

[GerberI]

Moved to #321