add optional sticker

[Ingo Steinke]

Add a "sticker" / "Störer" to promote special offers etc. visually similar to the one that announced [kleiderordnung.berlin](https://kleiderordnung.berlin/] on kleiderordnung-duesseldorf.de

[Ingo Steinke]

new style draft:

background: var(--color-dark-red-pinkish);
color: var(--color-default-white);
position: absolute;
top: 10rem;
right: 0;
z-index: 2;
transform: rotate(45deg);

^ backend (mu-plugin)

frontend similar but

• other position or parent
• explicit font size etc. if necessary
• explicit min/max sizing, overflow behavior etc.

Content: possibly another custom content type, so we have out of the box

• internationalization
• draft/prepare and view campaigns history
  and we will only show the latest active one in the current language.

Fields:

• text (may use formatted rich text)
• link target

[Ingo Steinke]

don't overcomplicate, and adapt the default colors to the women's day special offer poster, but slightly more pastel to match the page intro as well

poster + sticker:

intro + sticker: