WIP - Improve metric name creation to be unique

[JorTurFer]

Signed-off-by: jorturfer [email protected]

This draft shows the approach that I propose to generate unique metric names in base of the trigger values. All the scalers will contain an option in trigger named metricName which supports setting specific metric name instead generate if from hashing result. All the metric names will be composed using the pattern scalerType-metricName

I have just tried the change passing mssql e2e tests and it works really fine. Of course, this PR needs a lot of effort yet because all the scalers should be updated, but I'd like to get your opinion about the approach before update all the scalers.
@tomkerkhove @zroubalik
Could you share your thoughts?

Checklist

• Commits are signed with Developer Certificate of Origin (DCO - learn more)
• Tests have been added
• A PR is opened to update our Helm chart (repo) (if applicable, ie. when deployment manifests are modified)
• A PR is opened to update the documentation on (repo) (if applicable)
• Changelog has been updated

Updated scalers:

• ActiveMQ Artemis
• Apache Kafka
• AWS CloudWatch
• AWS Kinesis Stream
• AWS SQS Queue
• Azure Blob Storage
• Azure Event Hubs
• Azure Log Analytics
• Azure Monitor
• Azure Pipelines
• Azure Service Bus
• Azure Storage Queue
• CPU
• Cron
• External
• External Push
• Google Cloud Platform‎ Pub/Sub
• Huawei Cloudeye
• IBM MQ
• InfluxDB
• Kubernetes Workload
• Liiklus Topic
• Memory
• Metrics API
• MongoDB
• MSSQL
• MySQL
• NATS Streaming
• OpenStack Metric
• OpenStack Swift
• PostgreSQL
• Prometheus
• RabbitMQ Queue
• Redis Lists
• Redis Lists (supports Redis Cluster)
• Redis Streams
• Redis Streams (supports Redis Cluster)
• Selenium Grid Scaler
• Solace PubSub+ Event Broker

Fixes #2123

[zroubalik]

I don't like hash appended to the metric name 😕 #2123 (comment)

[JorTurFer]

I don't like hash appended to the metric name 😕 #2123 (comment)

Let's continue the conversation there :)