✅(e2e) add specific accounts for testing

This creates a bunch of accounts with various profiles
to allow testing in a specific "mode"

docs/testsE2E.md

@@ -0,0 +1,51 @@
+# E2E tests
+
+## Run E2E tests
+
+``` bash
+# you need the dockers to be up and running
+make bootstrap
+
+# you will need to have few accounts in the database
+make demo FLUSH_ARGS='--no-input'
+
+# run the tests
+cd src/frontend/apps/e2e
+yarn test:ui --workers=1
+```
+
+A new browser window will open and you will be able to run the tests.
+
+## Available accounts
+
+The `make demo` command creates the following accounts:
+ - `jean.team-<role>@example.com` where `<role>` is one of `administrator`, `member`, `owner`:
+    this account only belong to a team with the specified role.
+ - `jean.mail-<role>@example.com` where `<role>` is one of `administrator`, `member`, `owner`:
+    this account only have a mailbox with the specified role access.
+ - `jean.team-<team_role>-mail-<domain_role>@example.com` with a combination of roles as for the
+    previous accounts.
+
+For each account, the password is `password-e2e-<username>`, for instance `password-e2e-jean.team-member`.
+
+In the E2E tests you can use these accounts to benefit from there accesses, 
+using the `keyCloakSignIn(page, browserName, <account_name>)`. The account name is the 
+username without the prefix `jean.`.
+
+``` typescript jsx
+await keyCloakSignIn(page, browserName, 'mail-owner');
+```
+
+The `keyCloakSignIn` function will sign in the user on Keycloak using the proper username and password.
+
+.. note::
+    This only works because the OIDC setting is set to fallback on user email.
+
+## Add a new account
+
+In case you need to add a new account for specific tests you need:
+- to create a new user with the same format in the backend database: 
+  update `[create_demo.py](../src/backend/demo/management/commands/create_demo.py)`
+- to create a new account in Keycloak: update [realm.json](../docker/auth/realm.json)
+- if the keycloak was running locally, you need to destroy its database and 
+  restart the database and the keycloak containers.