Remove TODO , wrapper class variable rename, Inject mappers

Fixes #406 (closed)

Changes :

• - Removed TODO function from mappers classes. Since there were very less mappers which were using both function , so I have removed interface , because there was no benefit of using that.
• - I have removed useCase suffix from wrapper class variable.
• - I have Injected all the mappers by keeping them into a wrapper class.

Screenshots for the change :
No visual changes.

**Appetize.io Link : **
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