Extracted switch-statement

Implemented new method "amountFor(Rental each)" that replaces the
functionality of the switch-statement in the constructor for the string
"statement".
rename variables and move method

moved method from customer class to rental class because it uses
information from the rental class
Renaming redundant variables

Replaced a temporary variable with a query to avoid to much parameters
being passed around.
Extracting and bugfixing

Extracted the functionality of increasing the "frequentRenterPoints"
variable into a new function in the class "Rental". Fixed a variable
naming error.
replace temps with querys for total amount and frequent render points
Added HTML generator for statement

Implemented a method for generating a HTML version of the string
"statement".
replacing the conditional logic on price code with polymorphism
Replaced conditional logic with polymorphism

Implemented class hierarchy for movies and adapted methods for each
child class. Removed switch statement as a result.