CPackDeb: Add option to set compression type

Add a CPACK_DEBIAN_COMPRESSION_TYPE option to set the compression type.
Default to 'gzip' to preserve existing behavior.  Use "cmake -E tar"
for 'gzip', 'bzip2', and 'none'.  Use system "tar" for 'lzma' and 'xz'.
Merge topic 'cpack-deb-compression-types' into next

13778cd3 CPackDeb: Add option to set compression type
Merge topic 'doc-cmake-developer-no-cmStdString'

328c2179 Help: Drop cmStdString from cmake-developer(7) examples
Merge topic 'fix-find_dependency-empty-version'

a25b809f Tests: Check find_dependency empty extra arguments
9914e7cd Merge branch 'fix-find_dependency-empty-version'
34cd5fc4 find_dependency: Give more helpful message if VERSION is empty
d363cbf3 Tests: Make RunCMake.find_dependency tolerate line number changes
Merge topic 'different-python-header-libs-exe-0013794'

59220198 FindPython*: Document suggested find_package order (#13794)
a9e6de2a FindPythonInterp: Use consistent version with PythonLibs (#13794)
Merge topic 'unicode-cmake-gui'

c34216cf cmake-gui: Fix compile with Qt5 using UTF-8 internal encoding.
Merge topic 'FeatureSummary_missing_titles'

1af77f3f FeatureSummary: Add missing titles for PACKAGES_FOUND and PACKAGES_NOT_FOUND
Merge topic 'cpack-deb-compression-types'

13778cd3 CPackDeb: Add option to set compression type
Merge branch 'master' into next