The /opt/bitnami/apache2/conf/httpd.conf file is the main configuration file of Apache. I just checked that the extensions that are mentioned in the Github guide you shared are enabled by default in our WildFly solution
Regarding the .htaccess configuration, Apache is only used to proxy the requests to the WildFly server as @michiel mentioned. However, the Apache's configuration file for WildFly is at /opt/bitnami/wildfly/conf/wildfly.conf so you can include all the wildfly-related configuration there. I understand that this configuration is because some functionalities of WildFly, right?