cleanup: Map test files according to structure in src

For example cmd_account() is located in src/command/cmd_funcs.c.
The unit test was located in tests/unittests/test_cmd_account.c.
Let's move it to a subdirectory like tests/unittests/command/test_cmd_account.c
to correpsond to the same structure.

tests/unittests/command/test_cmd_otr.h

@@ -0,0 +1,37 @@
+#include "config.h"
+
+#ifdef HAVE_LIBOTR
+void cmd_otr_log_shows_usage_when_no_args(void** state);
+void cmd_otr_log_shows_usage_when_invalid_subcommand(void** state);
+void cmd_otr_log_on_enables_logging(void** state);
+void cmd_otr_log_off_disables_logging(void** state);
+void cmd_otr_redact_redacts_logging(void** state);
+void cmd_otr_log_on_shows_warning_when_chlog_disabled(void** state);
+void cmd_otr_log_redact_shows_warning_when_chlog_disabled(void** state);
+void cmd_otr_libver_shows_libotr_version(void** state);
+void cmd_otr_gen_shows_message_when_not_connected(void** state);
+void cmd_otr_gen_generates_key_for_connected_account(void** state);
+void cmd_otr_gen_shows_message_when_disconnected(void** state);
+void cmd_otr_gen_shows_message_when_undefined(void** state);
+void cmd_otr_gen_shows_message_when_connecting(void** state);
+void cmd_otr_gen_shows_message_when_disconnecting(void** state);
+void cmd_otr_myfp_shows_message_when_disconnected(void** state);
+void cmd_otr_myfp_shows_message_when_undefined(void** state);
+void cmd_otr_myfp_shows_message_when_connecting(void** state);
+void cmd_otr_myfp_shows_message_when_disconnecting(void** state);
+void cmd_otr_myfp_shows_message_when_no_key(void** state);
+void cmd_otr_myfp_shows_my_fingerprint(void** state);
+void cmd_otr_theirfp_shows_message_when_in_console(void** state);
+void cmd_otr_theirfp_shows_message_when_in_muc(void** state);
+void cmd_otr_theirfp_shows_message_when_in_private(void** state);
+void cmd_otr_theirfp_shows_message_when_non_otr_chat_window(void** state);
+void cmd_otr_theirfp_shows_fingerprint(void** state);
+void cmd_otr_start_shows_message_when_in_console(void** state);
+void cmd_otr_start_shows_message_when_in_muc(void** state);
+void cmd_otr_start_shows_message_when_in_private(void** state);
+void cmd_otr_start_shows_message_when_already_started(void** state);
+void cmd_otr_start_shows_message_when_no_key(void** state);
+void cmd_otr_start_sends_otr_query_message_to_current_recipeint(void** state);
+#else
+void cmd_otr_shows_message_when_otr_unsupported(void** state);
+#endif