Add Sales Grid implementation.

[skrustev]

There are currently 2 issues that need to be resolved for this PR:

1. Excel exporters are not available and there's already PR for it:
   feat(elements): Add excel and csv exporters to elements. igniteui-angular#15611
2. Setting headerTemplate during columnInit event breaks the grid and there are errors:
   fix(elements): Handle template setting of components passed as event args through proxy.  igniteui-angular#15649

Fixes IgniteUI/grid-demos#105 for WC as well.

[mddragnev]

Found 3 things:

1. Grid Height is not 100% of the viewport.
2. When changing views from the views dropdown nothing happens. It stays on the first view.
3. On the main view -> Remove Brand column -> an error is thrown

[MayaKirova]

In the sample itself:

• Small issue I noticed is that if you configure the pivot so that it has some empty values (Rows: All Periods + Country, Columns: Brand, Store), it shows them as $NaN:
  
  While in the angular sample, it shows an empty cell, which looks better.

In the whole app:

• When running npm run build there are some error thrown from the sample:
  

• When running the full app npm run dev and navigating to the target sample, there seems to be an issue with the theming:

[MayaKirova]

When run in preview, there are some errors and the data does not load:

If I remove the filter "Brands" it shows the data correctly.

[MayaKirova]

Also when running the individual sample, for some reason while dragging a chip it disappears:

It then appears when you drop it.

[skrustev]

T he issue with chips should be fixed now.
For the data loading make sure you install the latest packages in the projects run.