Fix prompt text overflow in create order

[forcryptos]

Added StringUtils class with truncatePromptText method.

truncatePromptText is called in MutableOfferView(5) and
in MutableOfferViewModel(1) to cut too long text.

Fixes #5189

[wallclockbuilder]

UtAck

[ripcurlx]

I think this should be handled differently. I'm quite sure the auto-truncation of the prompt text is a supported feature, but it just doesn't work because input.setMaxWidth(Double.MAX_VALUE); is set in getEditableValueBox. I didn't have time to look into it in more detail, but I think this is the way to fix this issue.