Add feature to customise the character count messages.

[Ibabalola]

We need to be able to customise these messages so that we can translate this text:

• Please offer a way for consumers to be able to specify their own dynamic messages using the maxLength, limitType, remainingCount and overLimitBy variables for each of these scenarios.

  const maxCharactersMessage = !hydrated
    ? `You can enter up to ${maxLength} ${limitType}.` // non-js
    : remainingCount >= 0
    ? `You have ${remainingCount} ${limitType} remaining` // js within the limit
    : `You have ${overLimitBy} ${limitType} too many`; // js outside the limit

[daniele-zurico]

closed by #428