Internationalize and Localize Budgeteer

[tinne]

There are a number of i18n and l10n issues connected to Budgeteer, which has been using (potentially singularly) in Germany for a while.

A project should have a locale configuration. This corresponds to the Un*x LANG variable. From it, the system should derive

• the language of the UI
• the charset of the UI
• the currency for the UI
• the date format for the UI
• the holiday scheme used for work day calculation (cf. Public Holiday Configuration)

The default country configuration shall be “de_DE.utf8” for backwards compatibility.

Any hard coded currency signs (cf. e.g. #441) shall be eliminated.

Error and information messages can start off in their transitional mostly English mode and shall be subsequently translated as being worked on (i.e., no complete German translation is necessary to complete this ticket).