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/xmpp/test_jid.h

@@ -0,0 +1,25 @@
+void create_jid_from_null_returns_null(void** state);
+void create_jid_from_empty_string_returns_null(void** state);
+void create_jid_from_full_returns_full(void** state);
+void create_jid_from_full_returns_bare(void** state);
+void create_jid_from_full_returns_resourcepart(void** state);
+void create_jid_from_full_returns_localpart(void** state);
+void create_jid_from_full_returns_domainpart(void** state);
+void create_jid_from_full_nolocal_returns_full(void** state);
+void create_jid_from_full_nolocal_returns_bare(void** state);
+void create_jid_from_full_nolocal_returns_resourcepart(void** state);
+void create_jid_from_full_nolocal_returns_domainpart(void** state);
+void create_jid_from_full_nolocal_returns_null_localpart(void** state);
+void create_jid_from_bare_returns_null_full(void** state);
+void create_jid_from_bare_returns_null_resource(void** state);
+void create_jid_from_bare_returns_bare(void** state);
+void create_jid_from_bare_returns_localpart(void** state);
+void create_jid_from_bare_returns_domainpart(void** state);
+void create_room_jid_returns_room(void** state);
+void create_room_jid_returns_nick(void** state);
+void create_with_slash_in_resource(void** state);
+void create_with_at_in_resource(void** state);
+void create_with_at_and_slash_in_resource(void** state);
+void create_full_with_trailing_slash(void** state);
+void returns_fulljid_when_exists(void** state);
+void returns_barejid_when_fulljid_not_exists(void** state);