[WIP] Add support for LD_LIBRARY_PATH_ELEMENT

Currently OpenShift does not manage the `LD_LIBRARY_PATH` for cartridge and they set/unset this environment variable as they want. This cause problems for Jenkins build and introduce situlations where two cartridges fighting for `LD_LIBRARY_PATH`. This PR should add support for managing this environment variable by Node, in similar matter that we manage `PATH` nowadays.

Cartridge writers can use LD_LIBRARY_PATH_ELEMENT variable to say what directory they want to append into the global `LD_LIBRARY_PATH`.

- [x] Add support for LD_LIBRARY_PATH_ELEMENT in `node/lib/openshift-origin-node/utils/environ.rb`
- [] Add unit tests for environ.rb
- [ ] Update mariadb cartridge
- [ ] Update mysql cartridge
- [x ] Update postgresql cartridge
- [ ] Update python cartridge
- [x] Update ruby cartridge
- [] Update nodejs cartridge
- [] Update zend cartridge
- [] Fix rhcsh so users can see LD_LIBRARY_PATH when the 'ssh' into gear.

- [] Update documention