feat: implement get columns/tables for transactional databases

[Ryuk-me]

Implement get_columns function for every database which will return column name and column type

It should take is_generic as a flag and return generic data type if it's true

Example

is_generic = False
[
  {
    "name": "first_name",
    "type": VARCHAR
  }
]

is_generic = True
[
  {
    "name": "first_name",
    "type": "string"
  }
]