Add the ability to add a gradient, and a gradient on top of image

Working on it.

Adding a patch or checkout the issue branch.

@siramsay I have reviewed the changes and the changes looks good. Although I have fixed some code formatting issue in your commit and after pushing code to a branch we need to create a MR into the branch we need to implement these changes . So raised a MR.
Attaching screenshot for reference . RTBC ++.

@sourabhsisodia_ Thanks for fixing the coding standards, my IDE put those curly brackets on the next line.

I am changing this back to needs work. Please cancel MR. I can't do that for some reason.

I am working on this.

With the default field length of 128 it was not possible to add long gradients such as the example below which is 210 char.
I have made the field max length 256 char.
I have added a help note below the field.

linear-gradient(217deg, rgb(255 0 0 / 80%), rgb(255 0 0 / 0%) 70.71%),
linear-gradient(127deg, rgb(0 255 0 / 80%), rgb(0 255 0 / 0%) 70.71%), 
linear-gradient(336deg, rgb(0 0 255 / 80%), rgb(0 0 255 / 0%) 70.71%)

New patch for longer gradient strings.

This works but could be better. People could add strings longer than 256 char.