Add support for osb_client_platform with value cloudfoundry or kubernetes

[gberche-orange]

Expected behavior

As an osb-cmdb backing service author

• in order to dynamically discover that osb-client platforms (mentionned as brokered_service_client_name in x-osb-cmdb) are using OSB originating platform header (typically cloudfoundry or kubernetes)
• I need to receive an osb_client_platform field with the value of the OSB originating platform header

Observed behavior

No such parameter osb_client_platform yet sent in x-osb-cmdb

Affected release

Reproduced on version x.y
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