Lp 1850156: Add <osname>-git Makefile.install targets

Lp 1850156: Add <osname>-git Makefile.install targets

Add <osname>-git Makefile.install targets for Ubuntu and Debian so
that one can build Evergreen from Git without needing to install
Chromium, Firefox, and all of the dependencies that they bring with
them.

The <osname>-developer target depends on the <osname>-git target, so
it can still be used as before to install from Git.  It brings in the
Chromium and Firefox dependencies.

The <osname>-translator Makefile.install target depends on the
<osname>-git target.  Translators are not required to run tests.

The <osname>-packager Makefile.install target still depends on the
<osname>-developer target because packagers are expected to run tests.

To test these changes, one pretty much has to set up a virtual machine
for each support value of <osname> and run each Makefile.install
target one at a time to see that the appropriate dependencies are
brought in.  It is recommended to refresh the VM after each test.

Signed-off-by: Jason Stephenson <jason@sigio.com>