Migrate "personal" config in tests to new-style XDG config dir

Signing key configuration is obviously something that belongs to the
user's macros, but lets get on with the times and use the new XDG config
directory for that.

The remaining references to ~/.rpmmacros in rpmmacro.at are related to
testing behavior with the old-style configuration and need to be preserved.

This is the fourth and final step to rpm-software-management#3521.

Fixes: rpm-software-management#3521

tests/mktree.common

@@ -29,4 +29,7 @@ make_install()
     # gpg-connect-agent is very, very unhappy if this doesn't exist
     mkdir -p $DESTDIR/root/.gnupg
     chmod 700 $DESTDIR/root/.gnupg
+
+    # set up new-style XDG config directory
+    mkdir -p $DESTDIR/root/.config/rpm
 }

tests/rpmi.at

@@ -904,7 +904,7 @@ for e in 1 2; do
     runroot_other cp /build/RPMS/noarch/versiontest-1.0-1.noarch.rpm /tmp/epoch${e}.rpm
 done
 # for testing sanity
-echo '%_query_all_fmt %%{nevra}' >> ${HOME}/.rpmmacros
+echo '%_query_all_fmt %%{nevra}' >> ${HOME}/.config/rpm/macros
 
 RPMTEST_CHECK([
 RPMDB_INIT

tests/rpmsigdig.at

@@ -1398,7 +1398,7 @@ AT_SKIP_IF([test x$PGP = xdummy])
 RPMDB_INIT
 
 RPMTEST_CHECK([
-cat << EOF >> ${HOME}/.rpmmacros
+cat << EOF >> ${HOME}/.config/rpm/macros
 %_openpgp_sign sq
 %_openpgp_sign_id 771B18D3D7BAA28734333C424344591E1964C5FC
 EOF
@@ -1458,7 +1458,7 @@ AT_SKIP_IF([test x$PGP = xdummy])
 RPMDB_INIT
 
 RPMTEST_CHECK([
-cat << EOF >> ${HOME}/.rpmmacros
+cat << EOF >> ${HOME}/.config/rpm/macros
 %_openpgp_sign sq
 %_openpgp_sign_id 771B18D3D7BAA28734333C424344591E1964C5FC
 EOF
@@ -1568,7 +1568,7 @@ AT_SKIP_IF([test x$PGP = xdummy])
 RPMDB_INIT
 
 RPMTEST_CHECK([
-cat << EOF >> ${HOME}/.rpmmacros
+cat << EOF >> ${HOME}/.config/rpm/macros
 %_openpgp_sign sq
 %_openpgp_sign_id 771B18D3D7BAA28734333C424344591E1964C5FC
 EOF