Wifi security

[brainstorm]

Fixes issue #63 and readies SSH Stamp for security audit in #7.

Implements WPA2-WPA3 security by default... there seems to be a problem (bug?) with WPA3-only mode on esp_hal I need to investigate further: NetworkManager mis-identifies the network as WEP and PMF is disabled (should be enabled/mandatory in WPA3).

TODO:

• Move more of the console messages to debug!() instead of info!() so that the user sees the generated wifi password easily and can copy-paste it on their client easily.
• Investigate WPA3 issue on esp_hal.
• Test thoroughly on hardware.

[jubeormk1]

Overall I like the way this is looking! But there are a couple of things:

• The board starts and the wifi is up but I cannot reach by ping or ssh ssh-stamp. We need to review what has changed.
• Opinion: I would apply the WiFi ENV_VAR at once given that there is no error parsing SSID or PSK once all the environment variables have been processed as I mentioned in an inline comment.

[brainstorm]

The board starts and the wifi is up but I cannot reach by ping or ssh ssh-stamp. We need to review what has changed.

Weird, I just tested now and seems to work fine? A few checkpoints needed here:

1. Start with espflash erase-flash, just to make sure we start from known pre-conditions.
2. Make sure you delete the old hostkey from your ~/.ssh/known_hosts before re-flashing the device.
3. Does echo $SSH_STAMP_PUBKEY show an ed25519 pubkey before running ssh -o SendEnv=SSH_STAMP_PUBKEY zssh@192.168.4.1?
4. Before all that, do you "forget ssh-stamp access point on your client" and input the wireless PSK and does it connect alright?

This is what I'm seeing on my machine at the time of writing this on this branch as-is:

[jubeormk1]

While you have it fresh in your mind, could you add doc comments for what this function and wifi_up does? They retrieve the wifi_password and wifi_ssid from config.

Would it be reasonable defining these functions as part of config or you rather have them here because they are part of espressif configuration requirements?