make evictions_low_residence_duration_metric_threshold per-tenant (#3949)

Before this patch, if a tenant would override its eviction_policy
setting to use a lower LayerAccessThreshold::threshold than the
`evictions_low_residence_duration_metric_threshold`, the evictions done
for that tenant would count towards the
`evictions_with_low_residence_duration` metric.

That metric is used to identify pre-mature evictions, commonly triggered
by disk-usage-based eviction under disk pressure.

We don't want that to happen for the legitimate evictions of the tenant
that overrides its eviction_policy.

So, this patch
- moves the setting into TenantConf
- adds test coverage
- updates the staging & prod yamls

Forward Compatibility:
Software before this patch will ignore the new tenant conf field and use
the global one instead.
So we can roll back safely.

Backward Compatibility:
Parsing old configs with software as of this patch will fail in
`PageServerConf::parse_and_validate` with error 
`unrecognized pageserver option 'evictions_low_residence_duration_metric_threshold'`
if the option is still present in the global section.
We deal with this by updating the configs in Ansible.

fixes https://github.com/neondatabase/neon/issues/3940

.github/ansible/prod.ap-southeast-1.hosts.yaml

@@ -17,7 +17,7 @@ storage:
           kind: "LayerAccessThreshold"
           period: "10m"
           threshold: &default_eviction_threshold "24h"
-      evictions_low_residence_duration_metric_threshold: *default_eviction_threshold
+        evictions_low_residence_duration_metric_threshold: *default_eviction_threshold
       remote_storage:
         bucket_name: "{{ bucket_name }}"
         bucket_region: "{{ bucket_region }}"

.github/ansible/prod.eu-central-1.hosts.yaml

@@ -17,7 +17,7 @@ storage:
           kind: "LayerAccessThreshold"
           period: "10m"
           threshold: &default_eviction_threshold "24h"
-      evictions_low_residence_duration_metric_threshold: *default_eviction_threshold
+        evictions_low_residence_duration_metric_threshold: *default_eviction_threshold
       remote_storage:
         bucket_name: "{{ bucket_name }}"
         bucket_region: "{{ bucket_region }}"

.github/ansible/prod.us-east-2.hosts.yaml

@@ -17,7 +17,7 @@ storage:
           kind: "LayerAccessThreshold"
           period: "10m"
           threshold: &default_eviction_threshold "24h"
-      evictions_low_residence_duration_metric_threshold: *default_eviction_threshold
+        evictions_low_residence_duration_metric_threshold: *default_eviction_threshold
       remote_storage:
         bucket_name: "{{ bucket_name }}"
         bucket_region: "{{ bucket_region }}"

.github/ansible/prod.us-west-2.hosts.yaml

@@ -17,7 +17,7 @@ storage:
           kind: "LayerAccessThreshold"
           period: "10m"
           threshold: &default_eviction_threshold "24h"
-      evictions_low_residence_duration_metric_threshold: *default_eviction_threshold
+        evictions_low_residence_duration_metric_threshold: *default_eviction_threshold
       remote_storage:
         bucket_name: "{{ bucket_name }}"
         bucket_region: "{{ bucket_region }}"
@@ -34,7 +34,7 @@ storage:
     pageservers:
       hosts:
         pageserver-0.us-west-2.aws.neon.tech:
-          ansible_host: i-0d9f6dfae0e1c780d 
+          ansible_host: i-0d9f6dfae0e1c780d
         pageserver-1.us-west-2.aws.neon.tech:
           ansible_host: i-0c834be1dddba8b3f
         pageserver-2.us-west-2.aws.neon.tech:
@@ -49,5 +49,5 @@ storage:
         safekeeper-1.us-west-2.aws.neon.tech:
           ansible_host: i-074682f9d3c712e7c
         safekeeper-2.us-west-2.aws.neon.tech:
-          ansible_host: i-042b7efb1729d7966 
-          
+          ansible_host: i-042b7efb1729d7966
+

.github/ansible/staging.eu-west-1.hosts.yaml

@@ -17,7 +17,7 @@ storage:
           kind: "LayerAccessThreshold"
           period: "20m"
           threshold: &default_eviction_threshold "20m"
-      evictions_low_residence_duration_metric_threshold: *default_eviction_threshold
+        evictions_low_residence_duration_metric_threshold: *default_eviction_threshold
       remote_storage:
         bucket_name: "{{ bucket_name }}"
         bucket_region: "{{ bucket_region }}"

.github/ansible/staging.us-east-2.hosts.yaml

@@ -17,7 +17,7 @@ storage:
           kind: "LayerAccessThreshold"
           period: "20m"
           threshold: &default_eviction_threshold "20m"
-      evictions_low_residence_duration_metric_threshold: *default_eviction_threshold
+        evictions_low_residence_duration_metric_threshold: *default_eviction_threshold
       remote_storage:
         bucket_name: "{{ bucket_name }}"
         bucket_region: "{{ bucket_region }}"