Allow 'all-day' text to be translatable and set the time format uses on the calendar axis

[Pebblo]

See: https://eventespresso.com/topic/calendar-time-column/?view=all#post-326944

The changes in this branch allow for the default 'all-day' text used by full calendar to be translated.

It also adds a 'axis time format' option to the calendar settings to allow users to change the format used there.
(the default value for that option/parameter it what fullCalendar already uses)

How has this been tested

Go to Event Espresso -> Calendar

In basic settings you should have a 'Axis Settings' option and the default value should be h(:mm)tt

Open up the calendar in a new tab and check the Week and day views, confirm they show times on the left using the format 6pm.

In the settings again, change the format, for example, remove the tt and save, then confirm that value saves when you save the config.

Back to the front end calendar again, hard refresh and confirm the week and day views show the correct format (in this example, no AM/PM)

For the all-day text, install Pig Latin, activate it and confirm that with that plugin active the calendar displays something like allay-ayday, if so that string is now translatable.

Checklist

• I have read the documentation relating to systems affected by this pull request, see https://github.com/eventespresso/event-espresso-core/tree/master/docs
• User input is adequately validated and sanitized
• all publicly displayed strings are internationalized (usually using esc_html__(), see https://codex.wordpress.org/I18n_for_WordPress_Developers)
• My code is tested.
• My code follows the Event Espresso code style.
• My code has proper inline documentation.

[tn3rb]

Looks great, but it needs a couple minor tweaks

[Pebblo]

Thanks, Brent! Feeling a little rusty now as I should have picked up on those lol

Dismissed review as GitHub showed requested changes even though they were done.

Changes applied, github shows 1 remaining

[sethshoultes]

Testing Notes:

• I can't seem to get this working with the Axis Time format:
• • Here is my WP General Setting: https://www.screencast.com/t/lWeiWqs8WY
• • Here's my Calendar Basic Settings: https://www.screencast.com/t/xxdXctLTaog
• • This is the output I get in the calendar week and day views: https://www.screencast.com/t/LCWfUoMd98DA

Additional Testing Notes:

• on an existing install, the default value for "Axis Time Format" was missing
• on a fresh install, the default value for "Axis Time Format" is present
• (also, reproduced on calendar/master) I noticed that the "Custom" Time Format shows \c\u\s\t\o\m in the text field when selected and the settings are saved, no matter what is entered into the field: https://www.screencast.com/t/kTinyc73f

[sethshoultes]

@Pebblo did you see my notes above?

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[ghost]

Tested it and works as expected! 💯