As we can't refer to the project root dir in the module path, the
module path may now also be a relative directory which is then
taken as being relative to the project root path.
Moves the checkModulePresence() function into the Setup class, so
that it can work on the computed absolute module path.
CONST_BasePath is split into separate configuration variables
for binaries, libraries and data. These variables as well as
the installation path are now set in the executable directly and
no longer configurable via project settings.
This is the first step towards an installable software. The
executables should know per installation where to find their
necessary data to execute. Project configuration needs to be
restricted to settings that really concern the specific Nominatim
installation.
