Remove dead branches and set delete on merge as default

[zmiklank]

• [x] - httpd-container
• [x] - nginx-container
• [x] - s2i-php-container
• [x] - varnish-container
• [x] - mariadb-container
• [x] - postgresql-container
• [x] - s2i-nodejs-container
• [x] - s2i-python-container
• [x] - mysql-container
• [x] - redis-container
• [x] - s2i-perl-container
• [x] - s2i-ruby-container
• [x] - s2i-base-container
• [x] - common
• [x] - tfaga
• [x] - tfaga-wrapper
• [x] - build and push action

[zmiklank]

All repositories are now cleaned up o merged branches. Rest of the branches need to be analyzed one-by-one before their removal.

Also the default setting for removing merged branches was changed.