Refactor db handler interface

What file or files will be changed by the refactor Db handler code, model code for databases

Describe what changes will be made by the refactor

• refactor model functions like getFieldsInOrder and getValuesInOrder to become one function that returns an object with the fields as keys and their values as object values.

• Have db interface take a DbQuery model, which than has a function that returns the sql string.

• Have DbQuery model be extended by DbGet, DbDelete, and DbSet models that take the values relevant and produces the sql string as above.

Describe the benefits of the refactor

• Reduces coupling between model functions, don't need to ensure same order of the fields/values.

• Reduces coupling between db interface and rest of the code, no longer will need dbGet.course, dbDelete.course, etc.

• Provides structure to db handling, ensures improper raw strings won't happen.