Bills: create article positions

[haimich]

• add migration and seeds ✅
• adapt repo & services ✅
• implement itemListView ✅
• € and % for input fields ✅
• add validation ✅
• adapt BillsEditor ✅
• adapt BillsTable ✅
• adapt stats ✅
• rename all model files to *Model ✅

[haimich]

• Multi step: http://codepen.io/brettmichaelorr/pen/RaRZLe | http://codepen.io/eyaylagul/pen/xGpvmg
• http://codepen.io/kwab/pen/dPmNqm
• font awesome icon: https://blackrockdigital.github.io/startbootstrap-sb-admin-2/pages/forms.html
• nice validation: http://codepen.io/Wimski/pen/vLwamZ
• panel: http://codepen.io/dustinoverby/pen/qOxBgj | http://codepen.io/TLJens/pen/wBZqmB

Icons in input field

• http://codepen.io/junrillg/pen/lehHG

Bootstrap forms

[haimich]

• typische Steuersätze: 0, 7, 10, 19, 20, 8 (Schweiz) -> kann sich ändern!