Feature request: UPDATER_VPN_SERVICE_COUNTRIES/CITIES filter, vpnconfig api over socks, shared json/redis

[5andr0]

What's the feature 🧐

I really don't like the idea to spam a bunch of dns requests for all provider servers available.
Wouldn't it be better to also enable filters for just the server countries or cities in use by setting
UPDATER_VPN_SERVICE_COUNTRIES or UPDATER_VPN_SERVICE_CITIES ?

To avoid leaking information for the manual update, it would be nice to proxy the provider api requests. Preferably even shadowsocks working for dns requests aswell.

When using multiple gluetun containers, each of them has to update the full provider list and do dns requests.
This is quite redundant and it would be nice to have a single shared servers.json, only updated by one container.
However, looking at the code, the servers.json is only read on startup, but not during reconnects.
An option would be nice to reparse the servers.json on reconnects or even better use a shared redis to only parse the needed servers.

Extra information and references

No response

[github-actions]

@qdm12 is more or less the only maintainer of this project and works on it in his free time.
Please:

• do not ask for updates, be patient
• 👍 the issue to show your support instead of commenting
  @qdm12 usually checks issues at least once a week, if this is a new urgent bug,
  revert to an older tagged container image