DM templates refactoring: template and schema improvements

[bohdanyurov-gl]

I've created this issue to track process of code base update.

Template/schema checklist:

• Version "1.0.0" is added to the schema file
• Legacy DM resources are changed to GCP type providers
• Cross-project resource creation is supported
• Name field is optional. DM resource name is used if it is missing
• API versions are upgraded to the latest ones (@ocsig should be notified in the case of major upgrade)
• All properties are checked for compatibility: there are differences between legacy DM resources and type providers, some fields are missing, etc.
• All APIs calls have links to relevant API documentation page. Schema info field has list of all methods used. Add list of APIs that need to be enabled
• Schemas provide extended validation:
  • All objects with schema have additionalProperties: false
  • Arrays have uniqueItems: true where applicable
  • ENUMs are up to date and present where necessary
  • Default values are revised
  • String values with strict checks have regex patterns - too difficult to do for now
• Resource names are correctly prefixed: some templates define too common names for resources that could interfere with each other. This might be something that we don't want though but users are struggling with
• Unit tests for schemas are added - too difficult to do for now
• Integration tests pass
• Manual resource creation is done (including cross-project creation)

Template batch 1:

• autoscaler
• cloud_function
• cloud_router
• cloud_spanner
• cloud_sql
• folder
• gcs_bucket
• instance
• instance_template
• managed_instance_group
• network
• network/subnetwork
• project

Template batch 2:

• backend_service
• bastion
• bigquery
• firewall
• gke
• healthcheck
• iam_custom_role
• iam_member
• ip_reservation
• nat_gateway
• kms
• pubsub
• route

Template batch 3:

• dataproc
• dns_managed_zone
• dns_records
• external_load_balancer
• forwarding_rule
• haproxy
• internal_load_balancer
• logsink
• network_peering
• org_policy
• shared_vpc_subnet_iam
• ssl_certificate
• target_proxy
• url_map

Template batch 4:

• cloud_tasks
• cloudbuild
• forseti
• interconnect
• interconnect_attachment
• runtime_config
• stackdriver_metric_descriptor
• vpn