[Trinidad] config to set whether span or "input readonly" should be rendered

[Marco Grimm]

Hello altogether,

at the moment Trinidad renders a span if readOnly is set, but we would like
an "input readonly" to be rendered. Would it be possible to make this
configurable? And it would be very nice to have the possibility to render
"tabindex = '-1'" together with readonly, so that the focus does not go
through the "input readonly".

Thanks in advance
Marco Grimm