This reverts commit 332b089ad213a1aa89658fffd8f68c9064c6d3db as multiline descriptions require special formatting.
Make `CPACK_DEBIAN_PACKAGE_DESCRIPTION` fallback variable precedence match CPackRPM behavior as much as possible. This is technically a breaking change, but the new behavior is more consistent with expectation anyway. Closes: #16272
Support for setting different description for each component.