[UIK-4940][theme] init new package with tokens

[ilyabrower]

Changelog

@semcore/core

Changed

• Moved css-variables to separate package - @semcore/theme.

Motivation and Context

• Added new package @semcore/theme with all old logic about design tokens -> css variables.
• Moved preset for panda from core.

How has this been tested?

Manually

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue).
• New feature (non-breaking change which adds functionality).
• Breaking change (fix or feature that would cause existing functionality to not work as expected).
• Nice improve.

Checklist:

• I have updated the documentation accordingly.
• I have added new tests on added of fixed functionality.