Allow registering dynamic translations

[LiamMorrow]

In some use cases, other i18n solutions manage translations. In these cases, it is desirable to resolve the translations dynamically.

For example, I use tolgee as a way to create and manage translations. It already deals with resolving the locale, and potentially pulling new translations from a remote server. As such, it is not feasible to know the translations at build or app start time, or even resolve them immediately without using a fallback.

This PR just adds a mechanism to provide a function to the registerTranslation function, which will be called when getting the translation.

In my application, this looks like this:

import { registerTranslation } from 'react-native-paper-dates';
import { tolgee } from '@/services/tolgee';

registerTranslation('default', () => {
  const t = tolgee.t;
  return {
  // Note that if I created this object at app start, these dynamic values would not update or use tolgees fallback while it resolved them
    save: t('Save'),
    selectSingle: t('SelectDate'),
    selectMultiple: t('SelectDates'),
    selectRange: t('SelectPeriod'),
    notAccordingToDateFormat: (inputFormat) =>
      t(`DateFormatMustBe{inputFormat}`, { inputFormat: inputFormat }),
    mustBeHigherThan: (date) => t(`MustBeLaterThan{date}`, { date }),
    mustBeLowerThan: (date) => t(`MustBeEarlierThan{date}`, { date }),
    mustBeBetween: (startDate, endDate) =>
      t(`MustBeBetween{startDate}-{endDate}`, { startDate, endDate }),
    dateIsDisabled: t('DayIsNotAllowed'),
    previous: t('Previous'),
    next: t('Next'),
    typeInDate: t('TypeInDate'),
    pickDateFromCalendar: t('PickDateFromCalendar'),
    close: t('Close'),
    minute: t('Minute'),
    hour: t('Hour'),
  };
});