Change gray colors palette to Material Design palette

[ansivgit]

📝 Describe the refactoring task

Since we don't know what palette our constants are based on now, we would like to redefine the color constants according to the Material Design palette. And name the colors variables as color-gray-xxx.

📍 Code location

src/core/styles/_constants.scss

🛠️ Suggested improvement

E.g.our color variable $color-gray-400: hsl(0deg 0% 69%); // #afafaf will be changed to 400 from MD palette: $color-gray-400: hsl(204deg 3%, 71%); // #b3b6b8

ℹ️ Additional context

We need this so that we can interpolate the color palette (get colors like gray-700, gray-800 etc.)

✅ Definition of Done (DoD):

All gray palette is changed due MD palette

[oibioib]

I can fix this issue.