tests: update test_module for DNS verficiations and clean some tests
openssl tests: we don't manage the OpenSSL code, so these tests are useless. exsitence domain tests: commented as dynamic DNS updates can create new domains. configuration tests: configuration management has a lot changed, so we'll have to make new tests. Remove the code managing FUSE and use configuration files instead. Finally, ask ACME server to delete account key as it is only temporary files and we don't save them.