workspace: implement focus stealing prevention levels with simple heuristics for Wayland windows

This adjusts activation on focus stealing prevention level

• "extreme" to only work with a valid activation token (unchanged vs master)
• "high" to additionally work if a valid activation token was created for the matching app id
• "medium" to work like "high" (see !8061) to additionally work if the last interaction with the active window was the "enter" or "return" key, so that launching stuff from terminals still works
• "low" to be like "medium" + always allow new windows to be activated
• "none" to just allow activation unconditionally

Based on !7950 (merged) and !7953 (merged). cc #186