Remove hello multi-arch image build

Moved to https://github.com/containers/PodmanHello

Signed-off-by: Chris Evich <cevich@redhat.com>

contrib/hello/podman_hello_world.c

@@ -1,26 +0,0 @@
-//###
-//  ASCII art by the incomparable Máirín Duffy,
-//  duffy@redhat.com, Twitter: @mairin
-//  January 2022
-//###
-
-#include <stdio.h>
-int main() {
-    puts("\
-!... Hello Podman World ...!\n\
-\n\
-         .--\"--.           \n\
-       / -     - \\         \n\
-      / (O)   (O) \\        \n\
-   ~~~| -=(,Y,)=- |         \n\
-    .---. /`  \\   |~~      \n\
- ~/  o  o \\~~~~.----. ~~   \n\
-  | =(X)= |~  / (O (O) \\   \n\
-   ~~~~~~~  ~| =(Y_)=-  |   \n\
-  ~~~~    ~~~|   U      |~~ \n\
-\n\
-Project:   https://github.com/containers/podman\n\
-Website:   https://podman.io\n\
-Documents: https://docs.podman.io\n\
-Twitter:   @Podman_io");
-}