Remove qmake build files

Removes qmake as a build system for building Qt Creator itself.
Keep them for some tests that are not completely moved to CMake yet.

Change-Id: I846c6ef65626b6dfae6375fdc85d00677aa8c2fb
Reviewed-by: hjk <hjk@qt.io>
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/clangformat/clangformat-source.pri

@@ -1,8 +0,0 @@
-INCLUDEPATH += $$PWD
-
-HEADERS += \
-    $$PWD/clangformatconstants.h \
-    $$PWD/clangformatbaseindenter.h
-
-SOURCES += \
-    $$PWD/clangformatbaseindenter.cpp

src/plugins/clangformat/clangformat.pro

@@ -1,40 +0,0 @@
-include(../../qtcreatorplugin.pri)
-include(clangformat-source.pri)
-include(../../shared/clang/clang_installation.pri)
-
-include(../../shared/clang/clang_defines.pri)
-
-requires(!isEmpty(CLANGFORMAT_LIBS))
-
-LIBS += $$CLANGFORMAT_LIBS
-INCLUDEPATH += $$LLVM_INCLUDEPATH
-
-QMAKE_CXXFLAGS_WARN_ON *= $$LLVM_CXXFLAGS_WARNINGS
-QMAKE_CXXFLAGS *= $$LLVM_CXXFLAGS
-unix:!macos:QMAKE_LFLAGS += -Wl,--exclude-libs,ALL
-
-SOURCES += \
-    clangformatconfigwidget.cpp \
-    clangformatfile.cpp \
-    clangformatindenter.cpp \
-    clangformatplugin.cpp \
-    clangformatsettings.cpp \
-    clangformatutils.cpp
-
-HEADERS += \
-    clangformatconfigwidget.h \
-    clangformatfile.h \
-    clangformatindenter.h \
-    clangformatplugin.h \
-    clangformatsettings.h \
-    clangformatutils.h
-
-FORMS += \
-    clangformatchecks.ui \
-    clangformatconfigwidget.ui
-
-equals(TEST, 1) {
-    DEFINES += TESTDATA_DIR=\"R\\\"xxx($$PWD/tests/data)xxx\\\"\"
-    HEADERS += tests/clangformat-test.h
-    SOURCES += tests/clangformat-test.cpp
-}

src/plugins/clangformat/clangformat_dependencies.pri

@@ -1,7 +0,0 @@
-QTC_PLUGIN_NAME = ClangFormat
-QTC_LIB_DEPENDS += \
-    extensionsystem \
-    utils
-QTC_PLUGIN_DEPENDS += \
-    cppeditor \
-    projectexplorer