feat: add SpoonCheckstyleCompliantPrettyPrinter to be compliant with Spoon's own formatting rules

We want to use Spoon to transform the code of Spoon. For this, we need a Spoon pretty-printer that is compliant with Spoon's checkstyle.

The idea is to create a class SpoonCheckstyleCompliantPrettyPrinter which extends DefaultJavaPrettyPrinter

Here are the rules with the number of violations in src/main/java today:

2 [modifierorder]
2 [rightcurly]
2 [unusedimports]
5 [regexpsinglelinejava]
77 [whitespaceafter]
99 [nowhitespacebefore]
167 [parenpad]
237 [regexpsingleline]
1629 [whitespacearound]