Enabled selective building of the individual components of the library

What is the new feature

The components interpolation and horizontal can be built selectively depending on whether they are needed or not

How is it implemented

Added two options BUILD_ICONMATH_INTERPOLATION and BUILD_ICONMATH_HORIZONTAL to enable this

Mandatory steps before review

• Gitlab CI passes (Hint: use make format for linting)
• New feature is covered by additional unit tests
• Mark the merge request as ready by removing Draft:

Mandatory steps before merge

• Reviewed by a maintainer
• Incorporate review suggestions
• Prior to merging, please remove any boilerplate from the MR description, retaining only the Please describe your feature in a couple of words and describe important implementation details of the feature section to maintain

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