More details on datagrid configuration

[petrbroz]

In the dashboard sample, go into more detail on how the datagrid component is configured, e.g.:

• here is how to create the empty grid
• here is how to add a title / header
• here is how to add row of data into the grid
• here is how to fill the table
• here is how to connect it with forge properties
• here is how to group it

[petrbroz]

Per @wallabyway's suggestion ☝️