[Outreachy Status Log] Generating a colored bar image

It has being a month since the last status log. Here is status of my progress:

- The architecture of the code has changed a lot since the last log. Several patches reviews were made between me and my mentor.

- The code now supports link validation, e.g, you can't turn on the streaming if the formats between subdevs are not compatible.

- It is more modular and easy to adapt to a dynamic topology configuration.

- Several bugs were corrected.

- The test pattern generator was imported from the vivid driver and now the code generates a non-grey image:

The next patch series will contain this test patter generator and the user will be able to configure the format of the image.

The next step is to work in a debayer block.