[v11.2.x] Canvas: Allow API calls to grafana origin (#94129)

Canvas: Allow API calls to grafana origin  (#91822)

* allow post URL
* check for config
* allow relative paths
* add allowed internal pattern; add checks for method
* update defaults.ini
* add custom header
* update config comment
* use globbing, switch to older middleware - deprecated call
* add codeowner
* update to use current api, add test
* update fall through logic

* Update pkg/middleware/validate_action_url.go

Co-authored-by: Dan Cech <dcech@grafana.com>

* Update pkg/middleware/validate_action_url.go

Co-authored-by: Dan Cech <dcech@grafana.com>

* add more tests

* Update pkg/middleware/validate_action_url_test.go

Co-authored-by: Dan Cech <dcech@grafana.com>

* fix request headers

* add additional tests for all verbs

* fix request headers++

* throw error when method is unknown

---------

Co-authored-by: Ryan McKinley <ryantxu@gmail.com>
Co-authored-by: Brian Gann <bkgann@gmail.com>
Co-authored-by: Brian Gann <briangann@users.noreply.github.com>
Co-authored-by: Dan Cech <dcech@grafana.com>
(cherry picked from commit f64b121ddb)

Co-authored-by: Adela Almasan <88068998+adela-almasan@users.noreply.github.com>

conf/sample.ini

@@ -411,6 +411,9 @@
 # Comma-separated list of plugins ids that won't be loaded inside the frontend sandbox
 ;disable_frontend_sandbox_for_plugins =
 
+# Comma-separated list of paths for POST/PUT URL in actions. Empty will allow anything that is not on the same origin
+;actions_allow_post_url =
+
 [security.encryption]
 # Defines the time-to-live (TTL) for decrypted data encryption keys stored in memory (cache).
 # Please note that small values may cause performance issues due to a high frequency decryption operations.