Use HTML entities whenever <ace> is used in UI-Text instead of regular opening/closeing chars

Problem/Motivation

The following translations are de facto untranslatable because they are containing <ace> :
https://localize.drupal.org/translate/languages/de/translate?project=ace...

The reason for this is, that Drupal's malformed html filter skips strings with unallowed / unknown tags. So the strings containing the <ace> are de facto untranslatable, because even if we translate them to any language importing will be skiped.

therefore whenever a regular opening tag or closeing is used iin ui text it should be replaced with html entities..

Steps to reproduce

Proposed resolution

use html entities instead of opening and closing tags in translation source strings containing the <ace> tag.

Remaining tasks

change UI translation strings

User interface changes

Change texts so that thexy will be translateaböe without using a legion of html tidy tools to figure out waht's wrong here..

API changes

none

Data model changes

none