Use devextreme-exceljs-fork

[Tucchhaa]

No description provided.

[wdevfx]

About demos urls, we missed the point that our demos urls contains ExcelJS direct mention
I guess it's okay and no blocker here, but let's clarify with PMs that it's ok

E.g link to the demo:
https://js.devexpress.com/jQuery/Demos/WidgetsGallery/Demo/DataGrid/ExcelJSOverview/MaterialBlueLight/
And as another example demo's redirect.json

[wdevfx]

Let's also change exceljs to our package in the webpack.config.js

As far as I understand, here is a list of external dependencies that should not be included in the artifacts bundles
So, just in case better to change it too