Multiple changes and fixes:

Common:
- renamed device type OPTICAL_LINE_SYSTEM to OPEN_LINE_SYSTEM
- added DATACENTER and EMULATED_DATACENTER device types.

Context:
- modified service constraints for test object to use nomenclature "metric[unit]"
- corrected ConstraintModel dump methods

Device:
- uncommented dump methods in database ContextModel and TopologyModel

OFC'22 / OECCPSC'22 tests:
- renamed device type OPTICAL_LINE_SYSTEM to OPEN_LINE_SYSTEM

WebUI:
OFC'22 / OECCPSC'22 tests:
- renamed device type OPTICAL_LINE_SYSTEM to OPEN_LINE_SYSTEM