Create keycloak SSO user for SSO testing

For Issue: https://repo1.dso.mil/platform-one/big-bang/bigbang/-/issues/1086

Using the new baby-yoda-ci.json realm config, we now have a config where MFA + email verification is disabled, as well as having any registered user automatically assigned to IL2. This MR adds a post deployment function to the CI that will leverage Keycloak's REST API and create a Cypress user for E2E testing.

Notes

• This function will only run on bb core packages IF .addons.keycloak.enabled == "true" in tests/dependencies.yaml
• This function will only run on bb's pipeline IF .addons.keycloak.enabled == "true" in tests/test-values.yaml
• The Keycloak documentation is incorrect and states that the request to create a user has only optional keys. Creating a user requires AT LEAST the keys specified in the CYPRESS_SSO_LOGIN variable.