Remove Duplicate Types, Create 'types' Folder in 'lib,' and Organize Related Types in Separate Files.

[vikaspatil0021]

https://github.com/calcom/cal.com/blob/6dec98129cd70f985889feb58a482480276dc1c3/packages/types/Calendar.d.ts#L75

1. Remove duplicate types from different files.
2. Create a types folder in lib.
3. Put related types in separate files.
4. Use .d.ts extension for type files.
5. use above link as reference