Polish some button styles (based on internal & external design review).

Ideally done in collab w/Anja during the sprint.

Login

• change login button to green button style

Sub app footer buttons

• change secondary button style to green outline & green font #599900

Sub app footer select box

• create new select box style according to this mock https://zpl.io/VD4Ye7W
• apply this style to all sub app & dialog footers (mainly language switcher, variant switcher, etc.)

Forms

• form field buttons:
  • change black button to button with rounded corners (same value as the green button)
  • button height: 35px
  • padding around button: 5px, centre-align in form field

Pages app

• change default and hover states for icon buttons in green components bar
  • they are not visible enough
  • try to improve by changing opacity