#553 - show statistics (number of accounts, transactions, ...)

.../deadlocker8/budgetmaster/controller/IndexController.java

...de/deadlocker8/budgetmaster/statistics/StatisticItem.java

...eadlocker8/budgetmaster/statistics/StatisticsService.java

src/main/resources/languages/base_de.properties

src/main/resources/languages/base_en.properties

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

src/main/resources/templates/statistics.ftl