Add support for views (query only)

[yorek]

Hawaii should also allow views to be exposed. They should behave like regular tables and support both queries and mutations. Not all columns returned by a view can be used in a mutation. For example, columns created from expressions will not be usable in mutations.

[seantleonard]

For execution, proposing to break this up in stages: implement view support for queries and, subsequently, mutations.

@ayush3797 when continuing MSSQL View implementation, approach the view support (querying only right now) as:

1. View representing 1 table with all columns
2. View representing 1 table with subset of columns
3. View representing multiple tables with all/subset of columns

Next, we'll need to further discuss expected behavior for supporting mutations for views. Especially when a view includes only a subset of columns of the backing table, and what the database metadata provider reads into the config data structure.

[Aniruddh25]

@ayush3797, I created #378 for view mutations.