Generate version header when configuring project

The basic idea is we create a version header template at
"src/base/version.h.in" and the build systems are expected to replace
strings that are enclosed with @ symbols and generate
"src/base/version.h" for other source files to consume/include.

src/base/base.pri

@@ -86,7 +86,8 @@ HEADERS += \
     $$PWD/utils/password.h \
     $$PWD/utils/random.h \
     $$PWD/utils/string.h \
-    $$PWD/utils/version.h
+    $$PWD/utils/version.h \
+    $$PWD/version.h
 
 SOURCES += \
     $$PWD/asyncfilestorage.cpp \