Clarify/update natural vs. full width controls in readonly modes

[ebruchez]

Following #6707.

Controls with "Field width" setting:

• Number
• Currency
• US Phone Number
• Date
• Time
• Date and Time

New/Edit mode:

View mode:

PDF:

Issue is that in View/PDF, only Date and Time take their "natural" (which means, in fact, "fixed") width. The others don't. Options:

• Should "natural" be ignored in view/PDF modes?
• Or should Number, Currency, US Phone Number, and Date and Time also take their "natural" width?

[ebruchez]

Reminder:

• We used to have only "natural", and with 2018.2 we introduced "full", since we can control widths with cells.
• Forms created with 2018.2 and newer default to "full", older forms to "natural".

This means that the "natural" width is probably rarely used anyway.