Increase the timeout on plugin download

[ldez]

What does this PR do?

Increase the timeout on plugin download

Motivation

Fixes #9512

More

• [ ] Added/updated tests
• [ ] Added/updated documentation

[nmengin]

LGTM

[milindpatel63]

I have had exact same issue as to this one #9512 since I have setup traefik for more than a year now. If it is a network issue it has been consistent for me for more than a year now.
Basically almost every time my server restarts or my traefik container get's updated via watchtower and restarts, either it goes fine 10% of the time, or i'l have to manually check docker logs to find that plugin has not loaded due to a network issue, and all my services are not working since they depend on that plugin as a middleware. I'll have to manually restart traefik docker container multiple times, sometimes like 30 times after which the plugin gets downloaded and everything works.

This has been a consistent issue for me. I have a pretty decent fiber internet 300up and 300down in India.

Here's the latest error

time="2023-04-07T08:16:06+05:30" level=info msg="Traefik version 2.9.10 built on 2023-04-06T16:15:08Z"
time="2023-04-07T08:16:07+05:30" level=info msg="\nStats collection is disabled.\nHelp us improve Traefik by turning this feature on :)\nMore details on: https://doc.traefik.io/traefik/contributing/data-collection/\n"
time="2023-04-07T08:16:22+05:30" level=error msg="Plugins are disabled because an error has occurred." error="failed to download plugin github.com/Paxxs/traefik-get-real-ip: failed to call service: Get \"https://plugins.traefik.io/public/download/github.com/Paxxs/traefik-get-real-ip/v1.0.2\": context deadline exceeded (Client.Timeout exceeded while awaiting headers)"

I looked into setting up local plugin repository for traefik, but wasn't able to set it up successfully, so I just gave up and added a manual task to reboot traefik container in my server spin-up checklist.

I really don't want to go back to NPM just cause of this stupid issue.

Edit:
I would love if there's a way to pass values via env variables on how many times the plugin download is retried in case of network issue and how much is the timeout on every retry.