fix typo in KorokPage: wicket can't found MembershipManagerBean
Custom exception page and email report only in production;
* code format
* small refactor
Move notification email strings of primary membership change to property file (#18)
Small refactors and cleanup
Refactor: move email strings of valuation message notifications to property file (#18)
* create private methods instead of a bunch of embedded try-if-else
* extract links to SystemManagerBean (for now)