feat: add ibm_event_streams_quota data source and resource

[kccox]

What has been done?

Add a data source and resource for the IBM Event Streams quotas.

• Quotas are created on an Event Streams service instance.
• Quotas define two rate limits, for producers and consumers. Rates are in bytes/second. A rate of -1 means no limit.
• A default quota can be created which applies to all users.
• A quota can also be created for a user, identified by IAM ID.

The quota data model used by both data source and resource is:

• resource_instance_id: The CRN of the Event Streams service instance. (Our existing models for topics and schemas also use this to identify the service instance.) Required in data source and resource.
• entity: "default", or the IAM ID of the user. Required in data source and resource.
• producer_byte_rate: The producer limit, using -1 for no limit. Computed in data source, required in resource.
• consumer_byte_rate: The consumer limit, using -1 for no limit. Computed in data source, required in resource.

The implementations use the Event Streams SDK client for our admin-rest API.

• The client is created similarly to the schema registry client:
  • config.go adds a client for this API using the SDK
  • The create/read/update/delete functions initialize the client with the REST endpoint (kafka_http_url)

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Closes internal Event Streams feature request from BNPP

Output from acceptance testing:

$ make testacc TEST=./ibm/service/eventstreams TESTARGS='-run=TestAccIBMEventStreamsQuotaDataSource\|TestAccIBMEventStreamsQuotaResource'
==> Checking that code complies with gofmt requirements...
TF_ACC=1 go test ./ibm/service/eventstreams -v -run=TestAccIBMEventStreamsQuotaDataSource\|TestAccIBMEventStreamsQuotaResource -timeout 700m
  (skipping many warnings to set environment variables not used by this test)
=== RUN   TestAccIBMEventStreamsQuotaDataSource
--- PASS: TestAccIBMEventStreamsQuotaDataSource (54.73s)
=== RUN   TestAccIBMEventStreamsQuotaResource
--- PASS: TestAccIBMEventStreamsQuotaResource (67.78s)
PASS
ok  	github.com/IBM-Cloud/terraform-provider-ibm/ibm/service/eventstreams
...

[uchenwankwo]

LGTM
-- Uche Nwankwo (OM for Event Streams)

[hkantare]

check other client session creation for visibility . If visbility is private then we construct service endpoint with private does your serivce support private endpoints

[kccox]

Visibility doesn't apply in our case, we do not set visibility in the client session. The code interacts with an instance of the Event Streams service which the user has provisioned. The endpoint is determined by a URL exposed in the instance metadata.

[hkantare]

Can you migrate to new error framework as announced in different slack channels

[kccox]

I have migrated to the flex framework, and also updated #5621.