Promote region* compute services to GA

[modular-magician]

Many of the region* resources are still marked as beta (at least for terraform). Some beta-restrictions were lifted in the past:

• 1a509e2698d173896c52cefd7bebb6a586e98308
• 0cb7099ddf8f72e3f9cc683f639d1f9321dc8c02

But others still seem to be missing. Anything holding us back from promoting all the Region* resources to GA?

Release Note Template for Downstream PRs (will be copied)

`google_compute_region_url_map` is now GA

`google_compute_region_target_http_proxy` is now GA

`google_compute_region_target_https_proxy` is now GA

compute: Promoted the following `google_compute_backend_service` fields to GA: `circuit_breakers`, `consistent_hash`, `custom_request_headers`, `locality_lb_policy`, `outlier_detection`

compute: Promoted the following `google_compute_region_backend_service` fields to GA: `affinity_cookie_ttl_sec`,`circuit_breakers`, `consistent_hash`, `failover_policy`, `locality_lb_policy`, `outlier_detection`, `log_config`, `failover`

Derived from GoogleCloudPlatform/magic-modules#3381