- Editable tags were still editable if the select was readonly
- LinkTo could still select an app (readonly not passed on)
- Hide the dropdown for multi-select when readonly
- Dates have their input as slotted, not internal
- Selects have .select_options, not .get_select_options()
- Remove this.egw().lang() use from Et2InvokerMixin._invokerTemplate()
Paying more attention to the WebComponent life cycle here, rather than what our widgets do - connectedCallback(), requestUpdate(), updated() are more important than loadFromXML(), etc. which are only used when loading from the .xet the first time.
