Allow negative integer for offsetX/offsetY options

[romanresh]

In my test I need to drag an element (source) to the right side of another element (target). So, I use this code:
await t.dragToElement(source, target, { offsetX: -10 });
but this exception occurs: "The "offsetX" option is expected to be a positive integer, but it was -10.".

Provide the capability to set offsetX/offsetY options with negative number.

[helen-dikareva]

Offset options define a point inside source element. Now we don't have offset options to target element, so may be we should implement it.

[romanresh]

Clarification:

• negative offsetX means offset from right side;
• nagative offsetY means offset from bottom side