Improve onboarding experience when user is connecting resources

[I-Dont-Remember]

tl;dr connecting resources is a friction point for new users before they see the value of Windmill - try to catch them by making it a smoother process

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As a first time user trying out Windmill, I played around in the demo for a little while, but very quickly wanted to get my hands dirty with some of my own databases/tools.

It seems like a potential point for onboarding users to drop off if there's too much friction before they can try out Windmill with their own data; since connecting to databases/AWS/etc. isn't a part that shows off the value prop of Windmill.

One small improvement towards that end, though I don't think it should be considered finalized, is helping people that want to connect to databases behind firewalls/security groups from the hosted Windmill app. An example of this is Retool providing specific instructions on the IPs that need to be white-listed before a DB connection will successfully go through.

[rubenfiszel]

Thank you for the effort you put into this issue.

The example you've shown for mysql is a great one. There are 2 subtasks for us: 1) have a set of static ips that we would show in the frontend (and in the documentation if they are truly static) 2) show them at time of adding a resource for some types

For 2), the set can be hardcoded in the frontend and one can already retrieve the workers actual ips. For 1), a little bit of work need to be done as we are using eks but it seems that this might do the trick: https://blog.damavis.com/en/adding-static-outbound-ips-in-amazon-eks/

[rubenfiszel]

Adding to this issue, adding a connection tester for postgresql and mysql

[rubenfiszel]

In latest commit, the first feature request is done. IPs to whitelist are shown for postgresql and mysql

[rubenfiszel]

second item also done