Fix Volume provisioning service instance parameter validation

[kumarashit]

What type of PR is this?

Uncomment only one /kind <> line, hit enter to put that in a new line, and remove leading whitespace from that line:

/kind new feature
kind bug fix
/kind cleanup
/kind revert change
/kind design
/kind documentation
/kind enhancement

What this PR does / why we need it:
This make the request parameter keys in accordance with the swagger.
a) Change the Key case
b) If the parameter is defined in action yaml to be required false, it sends the parameter as 'null'. This invalidates the default parameter value of the function and the SODA API fails for validation. So passing the default values explicitly

Some errors in API log:
E0706 12:58:42.250396 2799048 validation.go:64] invalid request: Request body has an error: doesn't match the schema: Property 'name' is missing
E0706 12:58:42.256562 2799048 context.go:155] code: 400, reason: Request body has an error: doesn't match the schema: Property 'name' is missing

I0706 23:04:09.462377 2892953 accesslog.go:26] ^[[32m[D] 172.23.0.6:37156 -- POST /v1beta/94b280022d0c4401bcf3b0ea85870519/block/volumes^[[0m
E0706 23:04:09.462515 2892953 validation.go:69] invalid request: Request body has an error: doesn't match the schema: Error at "/availabilityZone":Value is not nullable {"ProfileId": "868a7d24-74ac-41b4-8ef3-9e974f19a03d", "profileId": "868a7d24-74ac-41b4-8ef3-9e974f19a03d", "availabilityZone": null, "name": "test001", "size": 1}
E0706 23:04:09.462951 2892953 context.go:155] code: 400, reason: Request body has an error: doesn't match the schema: Error at "/availabilityZone":Value is not nullable

Which issue(s) this PR fixes:

Fixes #102

Test Report Added?:

Uncomment only one /kind <> line, hit enter to put that in a new line, and remove leading whitespace from that line:
/kind TESTED
kind NOT-TESTED

Test Report:

Volume provisioning in SODA Dashboard

Volume provisioning in Stackstorm

Bucket migration in SODA Dashboard:

Bucket MIgration in Stackstorm:

Special notes for your reviewer:

[joseph-v]

LGTM

[wisererik]

LGTM

[skdwriting]

LGTM