x-osb-cmdb fields and osb-cmdb annotations fields have inconsistent namings

[gberche-orange]

Expected behavior

As a backing service broker author

• in order to avoid copy/paste errors when parsing x-osb-cmdb fields
• I need a consistent naming of fields

Observed behavior

Some fields have camelcase naming e.g. brokered_service_context_spaceName , some others have _ as separators e.g. brokered_service_context_space_guid

Posssible approach

Introduce a new x_osb_cmdb_v2 param with better naming, see related #100

Affected release

Reproduced on version 1.5.0
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