add dms resources

[edisonxiang]

What this PR does / why we need it:

add dms service:

• add queue resource
• add group resource
• add instance resource
• add availablezone resource
• add maintainwindow resource
• add product resource

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:

Release note:

NONE

[coveralls]

Pull Request Test Coverage Report for Build 114

• 0 of 4 (0.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.06%) to 65.796%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
openstack/client.go	0	4	0.0%

Totals
Change from base Build 102:	-0.06%
Covered Lines:	3024
Relevant Lines:	4596

---

💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 111

• 0 of 4 (0.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.06%) to 65.796%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
openstack/client.go	0	4	0.0%

Totals
Change from base Build 102:	-0.06%
Covered Lines:	3024
Relevant Lines:	4596

---

💛 - Coveralls