Refactor: Sparkle Writers should be initialized inside class

[farbodahm]

In the current interface for Sparkle, we are passing Writers as writers: List[Writer]. it should be refactored to writers: List[type[Writer]], similar to readers argument.

Regarding type List[type[Writer]], it can be refactored to an Enum; So instead of List[type[Writer]], we accept List[WriterType] which WriterType is an enum. Same should happen for reader. (Created #24 another issue)

Reason is initiaizing a Writer requires a SparkSession which we decided to let Sparkle create that session; So it means during initializing a Sparkle app, we don't have access to SparkSession yet and Sparkle should be responsible for initializing Readers and Writers.

[wtfzambo]

@farbodahm didn't we suggest in our call to instead of passing writers: List[type[Writer]], to use some kind of Enum or TypedDict instead, to hide implementation away from final user and avoid unnecessary imports?

[farbodahm]

@wtfzambo That's a different story. I updated description of this issue to also include that.

[farbodahm]

@wtfzambo I created #24 to address that issue; For now I would prefer to keep it like this and continue developing Damavand to have something working.