Row selection has been disabled because bulk delete functionality
cannot work for array sub table according to the current implementation.

Bulk delete problem:

Suppose we have an array with values `[a, b, c]`. Suppose, the indexes
to be removed are [1, 2]. The UI asks firebase function to remove index
1. After 1, the UI asks index 2 to be deleted but index 2 doesn't exist.
After deletion of index 1, the array is `[a, c]`.

`enableRowSelection` was introduced in the last commit.

As of this commit row selection is enabled for TablePage and
SubTablePage.

If there are 1000 rows and we have rendered 100 then select all will
only select 100. In this case, technically all rows in react-table are
selected but we should not show the checked state. It leads to bad UX.
Indermediate would be better.

Also, split the additions of row selection column into a new useMemo. This
ensures that if a row is selected we are only re-calculating the row
selection column and not all.

Due to wrong CSS we were not able to see the icon.