add cce service v3 cluster and node interfaces

[Savasw]

What this PR does / why we need it: This PR adds CCE service interfaces

Which issue this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged): fixes #

Special notes for your reviewer:NONE

Release note:NONE

[coveralls]

Pull Request Test Coverage Report for Build 175

• 180 of 237 (75.95%) changed or added relevant lines in 6 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.3%) to 63.314%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
openstack/cce/v3/nodes/results.go	15	17	88.24%
openstack/cce/v3/clusters/results.go	10	12	83.33%
openstack/cce/v3/nodes/requests.go	81	98	82.65%
openstack/cce/v3/clusters/requests.go	59	95	62.11%

Totals
Change from base Build 173:	0.3%
Covered Lines:	3978
Relevant Lines:	6283

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💛 - Coveralls

[freesky-edward]

LGTM, one comment is it is not necessary to add okcodes definition if the ok code is default.