[5.1] Replace deprecated KeyboardEvent code

[C-Lodder]

Summary of Changes

Both the keypress event and keyCode property are deprecated in Javascript. This PR replaces them accordingly.

Testing Instructions

Calendar:

Open a calendar and ensure:

1. Shift + Space appends the date to the input.
2. ESC closes the calendar.
3. Tab closes the calendar.
4. The arrow keys (↑, ↓, →, ←) navigate through the calendar accordingly.
5. Repeat step 4 in RTL mode.

Web Install:

1. Go to administrator/index.php?option=com_installer&view=install, then navigate to the "Install from Web" tab.
2. Enter a phrase in the "Search" field.
3. Press Enter.
4. The search should be initiated.

@dgrammatiko I removed the following conditional statement:

if (ev.target === this.inputField && !(K>48 || K<57 || K===186 || K===189 || K===190 || K===32)) {
  return stopCalEvent(ev);
}

because I could not meet the condition, and using K > 48 || K < 57 makes no sense. It's possible that this was a mistake but the code doesn't contain any comments, sol....

[Fedik]

Please use event.code instead of event.key, because the key is altered by keyboard locale and layout. And code always represents a physical key on the keyboard.

[dgrammatiko]

It's possible that this was a mistake but the code doesn't contain any comments

the conditional is basically a way to ignore keys other than the ones actually used by the calendar but not sure if there’s a need for it. This is code from the early 2000’s so who knows anymore…

[C-Lodder]

@Fedik Oops, done

[Quy]

In RTL, the left key moves to the right and right key moves to the left. Not sure if this is the correct behavior as this is not the case without this PR.

[C-Lodder]

@Quy Fixed RTL. Thanks for testing

[Fedik]

@Quy are you sure?
To me, it sounds very strange, but I cannot really check, or find any info about it.
The codes represents a physical keys on keyboard, With physical direction Up/Down/Lft/Rgt which should not changes, no matter what.

[Quy]

I have tested this item ✅ successfully on 0625506

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[Quy]

@Fedik I was pointing out that this PR did the opposite for left/right keys which has been fixed since.

[viocassel]

I have tested this item ✅ successfully on 0625506

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[Quy]

RTC

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[LadySolveig]

Thank you @C-Lodder and also for testing, support and review @dgrammatiko @Fedik @Quy @viocassel