Ninja-based modules, like MesonModule and CMakeModule, need a way to
control the arguments passed to Ninja — mostly, the ability to set the
`-j 1` argument to disable parallel builds.

We tried with commit f8c05196 to overload makeargs for that, but it
had to be reverted because, unsurprisingly, make and ninja have
different ideas about what arguments are valid, and jhbuild has global
options for Make arguments.

Let's try again, this time introducing a NinjaModule base class, in
parallel to the existing MakeModule one; the NinjaModule class can do
all the Ninja discovery and execution, and control the configuration
options — both global and per module.

The MesonModule class can inherit straight from NinjaModule, thus
removing all the ad hoc code that used MakeModule for the set up, but
then ignored its `make()` method.

The CMakeModule is a bit of a nasty case, as CMake can have both a Make
and a Ninja backend, which means we need to inherit from MakeModule and
NinjaModule; luckily, both MakeModule and NinjaModule inherit from the
shared Package class, so we don't have conflicting initializations.

https://bugzilla.gnome.org/show_bug.cgi?id=782320