cmake: use legacy layout for static-build bundled libs

SVACE stopped working after commit 98b38e89 ("cmake: allow to
bundle static dependencies in main project") changed the bundled libs
directory layout. To fix this, let's introduce the new cmake option
BUNDLED_LIBS_INSTALL_DIR and set it in static-build/CMakeLists.txt to
the legacy location. Also, let's use the legacy directories for each
external project's PREFIX, SOURCE_DIR, BINARY_DIR, and STAMP_DIR.

Follow-up #9242

NO_DOC=build
NO_TEST=build
NO_CHANGELOG=build