PAINTROID-399 Fix contrast of text color to background color

[foenabua]

https://jira.catrob.at/browse/PAINTROID-399

Added new colors according to the ticket. However it was not possible to change the color of the Color Picker Tab Icon with this since the icon is an image must be dealt separately. Furthermore the Color Picker Transparent Color which used a checkered grey-white image, which was also noticed by Google for contrast issues, was not adressed in the mock-ups in the ticket. However it is worth mentioning for future tickets.

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[juliajulie95]

Thank you!