Add new beforeColumnWrap and beforeRowWrap hooks

[budnix]

Context

The PR fixes an issue related to unfocusing the table using Tab key when the NestedHeaders plugin was enabled. To fix the error, it was necessary to introduce new hooks that help determine when the moment of row wrapping occurs.

beforeRowWrap hook

const hot = new Handsontable({
  beforeRowWrap: (isWrapEnabled: boolean, newCoords: CellCoords, isFlipped: boolean) => {
  
  }
});

beforeColumnWrap hook

const hot = new Handsontable({
  beforeColumnWrap: (isWrapEnabled: boolean, newCoords: CellCoords, isFlipped: boolean) => {
  
  }
});

Hooks' arguments

• isWrapEnabled: The argument tells whether the row and/or column wrapping is going to happen. There may be situations where the option does not work even though it is enabled. This is due to the priority of other options that may block the feature. For example, when the minSpareRows is defined, the autoWrapCol option is not checked. Thus, column wrapping is off;
• The newCoords may help determine what cell will be focused on after the wrapping operation;
• The isFlipped is set to true when the user reaches the last row/column, and the focus is moved to the first row/column or vice versa, false otherwise.

Miscellaneous changes

The two new methods were added to the CellCoords class. This includes:

• isRtl() that allows checking if the coordinates running in RTL layout direction mode;
• assign() that allows assigning coordinates from another CellCoords instance or from a literal object that is compatible with CellCoords schema (has row and/or col properties).

How has this been tested?

Types of changes

• New feature or improvement (non-breaking change which adds functionality)

Related issue(s):

1. fixes https://github.com/handsontable/dev-handsontable/issues/1499

Affected project(s):

• handsontable

Checklist:

• I have reviewed the guidelines about Contributing to Handsontable and I confirm that my code follows the code style of this project.
• I have signed the Contributor License Agreement
• My change requires a change to the documentation.

[AMBudnik]

Hooks were introduced in v14.0.0. Updated demo https://jsfiddle.net/qsedcahb/8/