MinIO Server releases and other fixes (#1172)

## Server release  RELEASE.2024-03-26T22-10-45Z 

- Adding info about node dashboard for Grafana.
- Also updates links to JSON files for other dashboards that were
incorrect.

*no related docs issue*

## Not a server release, but fixes:

- Corrects information about JSON policy file size limits.
- Adds information about limit on tags per object.
    
Closes #1134

## Server RELEASE.2024-03-21T23-13-43Z
    
- Adds new `user` envvar and config for REDIS notifications
- Simplifies and updates discussion of encryption keys for SSE
    
Closes #1169

## Staging info

- [SSE encryption key
simplification](http://192.241.195.202:9000/staging/server-updates/linux/administration/server-side-encryption.html)
- [Node Grafana metrics & JSON
links](http://192.241.195.202:9000/staging/server-updates/linux/operations/monitoring/grafana.html#minio-node-metrics-dashboard)
- [Policy size
limit](http://192.241.195.202:9000/staging/server-updates/linux/administration/identity-access-management/policy-based-access-control.html#policy-document-structure)
- [Object
tagging](http://192.241.195.202:9000/staging/server-updates/linux/administration/object-management.html#object-tagging)
- [mc tag
set](http://192.241.195.202:9000/staging/server-updates/linux/reference/minio-mc/mc-tag-set.html)
- [REDIS
User](http://192.241.195.202:9000/staging/server-updates/linux/reference/minio-server/settings/notifications/redis.html#user)

source/administration/identity-access-management/policy-based-access-control.rst

@@ -28,7 +28,7 @@ Tag-Based Policy Conditions
 
 .. versionchanged:: RELEASE.2022-10-02T19-29-29Z
 
-   Policies can use conditions to limit a user's access only to objects with a specific tag.
+   Policies can use conditions to limit a user's access only to objects with a :ref:`specific tag <minio-object-tagging>`.
 
    MinIO supports :s3-docs:`tag-based conditionals <tagging-and-policies.html>` for policies for :ref:`selected actions <minio-selected-conditional-actions>`.
    Use the ``s3:ExistingObjectTag/<key>`` in the ``Condition`` statement of the policy.
@@ -156,11 +156,11 @@ Policy Document Structure
 MinIO policy documents use the same schema as 
 :aws-docs:`AWS IAM Policy <IAM/latest/UserGuide/access.html>` documents.
 
-The following sample document provides a template for creating custom
-policies for use with a MinIO deployment. For more complete documentation on IAM
-policy elements, see the :aws-docs:`IAM JSON Policy Elements Reference
-<IAM/latest/UserGuide/reference_policies_elements.html>`.
-The maximum size for a policy document is 2048 characters.
+The following sample document provides a template for creating custom policies for use with a MinIO deployment. 
+For more complete documentation on IAM policy elements, see the :aws-docs:`IAM JSON Policy Elements Reference <IAM/latest/UserGuide/reference_policies_elements.html>`.
+
+The maximum size for any single policy document is 20KiB.
+There is no limit to the number of policy documents that can be attached to a user or group.
 
 .. code-block:: javascript
    :class: copyable