Chore: Group auth docker blocks (#54274)

* Move auth docker images to parent folder

* Add README file for auth parent folder

* Add grafana-authnz-team as code owner

* Update `devenv` docs

devenv/docker/blocks/auth/openldap-multiple/notes.md

@@ -0,0 +1,38 @@
+# Notes on Multiple OpenLdap Docker Block
+
+This is very similar to openldap docker block, but it creates multiple ldap servers instead of one.
+
+Any ldif files added to the prepopulate subdirectory will be automatically imported into the OpenLdap database.
+
+"admins-ldap-server" block contains admin group and admin users. The "ldap-server" block has all the rest of the users. See below for the full list of users.
+
+This blocks are here to help with testing multiple LDAP servers, for any other LDAP related development and testing "openldap" block should be used.
+
+## Enabling LDAP in Grafana
+
+Copy the ldap_dev.toml file in this folder into your `conf` folder (it is gitignored already). To enable it in the .ini file to get Grafana to use this block:
+
+```ini
+[auth.ldap]
+enabled = true
+config_file = conf/ldap_dev.toml
+; allow_sign_up = true
+```
+
+## Groups & Users
+
+admins
+  ldap-admin
+  ldap-torkel
+backend
+  ldap-carl
+  ldap-torkel
+  ldap-leo
+frontend
+  ldap-torkel
+  ldap-tobias
+  ldap-daniel
+editors
+  ldap-editor
+no groups
+  ldap-viewer