New file wizard

The new file wizards helps users to create a new file by
* setting up portfolios and accounts
* optionally adding investment instruments
  (for example securities from the DAX)

Signed-off-by: simpsus <bastian.kennel@gmail.com>
Improve new file wizard

Changes resulting from pull request comments:
* changed visibility
* closing intro page only if an editor was opened
* formatting
* skipping trailing spaces in suggest securities file
* prevent securitites from getting added twice
* disable table widgets to prevent selection
Layout of the new portfolio wizard page

* adapt layout to adapt to resizing of window
* use existing translated properties
* externalize remaining strings into translation files
Layout of the additional accounts wizard page
Layout of the proposed securities page
Add indices and proper names to security proposals
Merge branch 'feature_new_file_wizard'