Update system connection add & remove

Add new --farm flag to podman system connection add so that
a user can add a new connection to a farm immediately.
Update system connection remove such that when a connection is
removed, the connection is also removed from any farms that have it.
Add docs and tests for these changes.

Signed-off-by: Urvashi Mohnani <umohnani@redhat.com>

pkg/util/utils.go

@@ -167,6 +167,17 @@ func StringMatchRegexSlice(s string, re []string) bool {
 	return false
 }
 
+// IndexOfStringInSlice returns the index if a string is in a slice, otherwise
+// it returns -1 if the string is not found
+func IndexOfStringInSlice(s string, sl []string) int {
+	for i := range sl {
+		if sl[i] == s {
+			return i
+		}
+	}
+	return -1
+}
+
 // ParseSignal parses and validates a signal name or number.
 func ParseSignal(rawSignal string) (syscall.Signal, error) {
 	// Strip off leading dash, to allow -1 or -HUP