chore: improvements to keycloak local development (#26518)

* update keycloak docker image

* update realm file with a compatible realm

* import realm on start-docker command

Since bitnami's image does not support importing directly, the import of the test realm is done in the make file start-docker action

* Use official image from quay

* updated realm keycloak config

* final note about nickname attrib for saml

* add admin user

* update realm

* Updated from master

* Updated docs

* local typo

* use jq for ldap and saml

* updated readme

server/build/docker/keycloak/README.md

@@ -1,12 +1,39 @@
-Overwrite your SamlSettings section in your config.json file by running `make config-saml` and restarting your server. You will need to set the following `SamlSettings` in order to complete the setup:
-- Enable: true
-- FirstNameAttribute: "givenName"
-- LastNameAttribute: "surname"
+# Keycloak development environment
 
-Admin Login:
-- admin/admin
+## Setting up
 
-Users:
-- homer/password
-- marge/password
-- lisa/password
+### OpenID
+
+Overwrite your `OpenIdSettings` section in your config.json file by running `make config-openid` and restarting your server.
+
+- [Official OpenID with Keycloak documentation](https://docs.mattermost.com/onboard/sso-openidconnect.html)
+
+### SAML
+
+Overwrite your `SamlSettings` section in your config.json file by running `make config-saml` and restarting your server.
+
+- [Official SAML with Keycloak documentation](https://docs.mattermost.com/onboard/sso-saml-keycloak.html)
+
+### LDAP
+
+Overwrite your `LdapSettings` section in your config.json file by running `make config-ldap` and restarting your server.
+
+- [Official LDAP with Keycloak documentation](https://docs.mattermost.com/onboard/ad-ldap.html)
+
+## Credentials to log in
+
+- **Admin account**, used to log in to the Keycloak Admin UI:
+  - `admin`/`admin`
+
+- **User accounts**, used to log in to Mattermost:
+  - `homer`/`password`
+  - `marge`/`password`
+  - `lisa`/`password`
+
+## Updating the `realm-export.json`
+
+The `realm-export.json` file is automatically imported by the keycloak development container. If you make any modifications to this file or to the base configuration, export it by running a terminal in the container and running:
+
+```bash
+/opt/keycloak/bin/kc.sh export --realm mattermost --users realm_file --file /opt/keycloak/data/import/realm-export.json
+```