Add Fedora Server generic guest and host image descriptions

This is loosely based on the Server kickstart and ELN descriptions.
This covers both the disk image for running on ARM hardware as well
as the VM image for running on various hypervisor platforms.

tmt/plans/server/guest/build-generic.fmf

@@ -0,0 +1,9 @@
+summary: Build Generic guest image
+discover:
+    how: fmf
+environment:
+    image_type: oem
+    image_profile: Server-Guest-Generic
+    kiwi_file: Fedora.kiwi
+execute:
+    how: tmt

tmt/plans/server/host/build-generic.fmf

@@ -0,0 +1,9 @@
+summary: Build Generic host image
+discover:
+    how: fmf
+environment:
+    image_type: oem
+    image_profile: Server-Host-Generic
+    kiwi_file: Fedora.kiwi
+execute:
+    how: tmt