Create LDAP container for ddev environment

For development purposes there must be a ldap container usable in the ddev environment.

It must be populated with dummy data, that can be used together felogin of the ddev instance.

• Create ldap container and make accessible from the web container
• Set correct binddn
• Implement TYPO3 schema
• Create dummy data for ldap in ldif format
• Create corresponding fe_user data
• Provision both while container startup
• Add documentation