#258 - added dark them for accounts, payments, categories, settings and about

...eadlocker8/budgetmaster/controller/PaymentController.java

src/main/resources/languages/_de.properties

src/main/resources/static/css/dark/style.css

src/main/resources/static/css/style.css

src/main/resources/templates/about.ftl

src/main/resources/templates/accounts/accounts.ftl

src/main/resources/templates/accounts/newAccount.ftl

src/main/resources/templates/categories/categories.ftl

src/main/resources/templates/categories/newCategory.ftl

src/main/resources/templates/datePicker.ftl

src/main/resources/templates/header.ftl

src/main/resources/templates/index.ftl

src/main/resources/templates/login.ftl

src/main/resources/templates/navbar.ftl

src/main/resources/templates/payments/newPayment.ftl

src/main/resources/templates/payments/payments.ftl

src/main/resources/templates/settings.ftl