Filter out source files that are not actually sources, like pkg config
files and json.gen files.
To make the output more reproducible, replace the absolute source and
build directories with relative paths prepended with a marker like
/src_dir/ and /build_dir/.
Apply this to source file paths and to qt attribution json file paths.
Genex wrapped sources still need to be handled, but that will come in
a later change.
Amends 37a5e001277db9e1392a242171ab2b88cb6c3049
Task-number: QTBUG-122899
Task-number: QTBUG-130557
Change-Id: Ic38cd9df827c1da770c1f337bc4725748bed5560
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>
(cherry picked from commit 6e7f871edfd35174b40c7eb7386282bfe019f276)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
0eff69e5eb