Suppress wget progress bar (#865)

In our CI wget spams thousands of lines of the progress bar into the
output, making it hard to read. Turns out, it doesn't have an option to
just remove the progress bar, but explicitly directing wget's log to
stdout and invoking --show-progress sends that to stderr which we
redirect to dev/null. The downloaded size is still reported at regular
intervals, but --progress=dot:giga shortens that to one line per 32M
which is manageable.

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

- **Chores**
- Improved file download process to display clearer progress updates
during downloads.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

(cherry picked from commit 07d7fadb1a)
Signed-off-by: Nick Volynkin <nick.volynkin@gmail.com>

hack/e2e.sh

@@ -60,7 +60,7 @@ done
 
 # Prepare system drive
 if [ ! -f nocloud-amd64.raw ]; then
-  wget https://github.com/cozystack/cozystack/releases/latest/download/nocloud-amd64.raw.xz -O nocloud-amd64.raw.xz
+  wget https://github.com/cozystack/cozystack/releases/latest/download/nocloud-amd64.raw.xz -O nocloud-amd64.raw.xz --show-progress --output-file /dev/stdout --progress=dot:giga 2>/dev/null
   rm -f nocloud-amd64.raw
   xz --decompress nocloud-amd64.raw.xz
 fi