Framework: Required fields for tile layout

[swashbuck]

Subject of the issue

The required fields for the tile layout need looking into.

1. The _graphic property on the main component configuration is not required for the tile layout. However, if missing, it will throw an error about a missing _graphic property due to this line.
2. The _top, _left and _imageAlignment properties are not needed for the tile layout. These should be removed from the example.json and a note should also be made in the README.md.

Steps to reproduce

Add the "_useGraphicsAsPins": true option and add graphics to each item to use the tile layout.

Environment

• FW 5.40.3
• Hot Graphic 6.13.4