implemented full rtl support

[danielgindi]

Description

This PR completes the RTL behavior in such a way that:

1. Elements flow from right to left when rtl is set. The original Position struct has not changed, it still has a left property, which now means "horizontal start position". When in rtl, it will be the position from the right.
2. Dragging - works correctly in rtl mode. With minimal changes to the code.
3. Resizing - the same. The resize event has new properties to make it more semantic without testing for the rtl flag everywhere.

This closes the issue #819.

Checklist

• Created tests which fail without the change (if possible) - not possible, tests already fail on master
• All tests passing (yarn test) - the same tests fail on master
• Extended the README / documentation, if necessary - not necessary

[adumesny]

thank you for making the fixes! I have a few small tweaks

[danielgindi]

thank you for making the fixes! I have a few small tweaks

I resolved those comments

[adumesny]

please revert your changes here as every line (white space) have changed otherwise. Yes I can ingore in preview but still git histoty will show you as last person changing every lines.