Fix set cell at and some refactoring

[Yousif-FJ]

This PR fix issues with SetCellAt. SetCellAt Did not work correctly previously and inserted incorrect element into the DOM in certain situations. I need SetCellAt to work correctly for my other PRs.

While I was trying to figure out the problem with that function, I had to refactor something.

Here are the main benefits of these changes:

• SetCellAt will work, in case the cell being set is outside the current default view layout (larger than the initial 4x4).
• Read to use AddColumn and AddRow function on the UI will allow us to easily expand the default row and column count.
• Respect the LighSheetOptions defaultRowCount and defaultColCount.
• Untangle UI and main.ts, where previously the initial table was being created in main.ts while it being a UI concern.

Additional tests were added + some fixes to other tests.

[rafinutshaw]

an extra row is being created on load. I only put in data for 3 rows

[Yousif-FJ]

an extra row is being created on load. I only put in data for 3 rows

This is because the default row and column is 4. I didn't change it, same as before.

[rafinutshaw]

an extra row is being created on load. I only put in data for 3 rows

This is because the default row and column is 4. I didn't change it, same as before.

Default column was only being used if no data was provided as in for emply table view. If data is present we generate the table based on data's row, column

[Yousif-FJ]

an extra row is being created on load. I only put in data for 3 rows

This is because the default row and column is 4. I didn't change it, same as before.

Default column was only being used if no data was provided as in for emply table view. If data is present we generate the table based on data's row, column

Changed.