feat: add custom color option for cards

[Khusyasy]

Pull request

• Have you followed the guidelines in our Contributing document?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?

New Feature Submissions:

1. Did you lint your code locally before submission?
2. Did you test your feature thoroughly to ensure there are no bugs?
3. Does your feature introduce breaking changes?

Please describe your changes

• add feature card custom color selection
• add new color selection for custom color in the card edit modal
• in Card component, if the selected color starts with '#', use css style background-color and use getContrast for the text color

Additional context

Resolves #308

[trobonox]

Looks good, nice touch that you also considered the contrast calculation :)

[trobonox]

Thanks for your contribution, just tested it and it works great!

For the future just a little thing: my branch protection rules require all contributors to sign their commits. For now it's no big deal and I will merge this anyways, but if you want to commit again at some point or contribute to some bigger project maybe consider adding a GPG key and signing your commits :)

[Khusyasy]

I see thank you so much, I will consider setting GPG key and signing commits from now on