service discovery: add pagination and filtering support to info requests (#12552)

* services: add pagination and filter support to info RPC.
* cli: add filter flag to service info command.
* docs: add pagination and filter details to services info API.
* paginator: minor updates to comment and func signature.

website/content/api-docs/services.mdx

@@ -77,6 +77,23 @@ The table below shows this endpoint's support for
 - `:service_name` `(string: <required>)` - Specifies the service name. This is
   specified as part of the path.
 
+- `namespace` `(string: "default")` - Specifies the target namespace. This
+  parameter is used before any `filter` expression is applied.
+
+- `next_token` `(string: "")` - This endpoint supports paging. The `next_token`
+  parameter accepts a string which identifies the next expected service. This
+  value can be obtained from the `X-Nomad-NextToken` header from the previous
+  response.
+
+- `per_page` `(int: 0)` - Specifies a maximum number of services to return for
+  this request. If omitted, the response is not paginated. The value of the
+  `X-Nomad-NextToken` header of the last response can be used as the `next_token`
+  of the next request to fetch additional pages.
+
+- `filter` `(string: "")` - Specifies the [expression](/api-docs#filtering)
+  used to filter the results. Consider using pagination or a query parameter to
+  reduce resource used to serve the request.
+
 ### Sample Request
 
 ```shell-session