Improved WiFi setup

[zehnm]

This should fix, or at least improve, the initial WiFi setup.

• SSIDs containing spaces are handled correctly and don't corrupt the configuration files
  • Shell script calls from PHP are properly escaped
• Replaced wpa_supplicant scanning with iw for reliable network scanning
  • The output parsing is more complex with awk. The patterns are defined in an external progfile.

The issues with wpa_cli scan & wpa_cli scan_results were manifold:

• Initial network configuration failed due to missing /etc/wpa_supplicant directory

• Initial network scan at first boot never worked for me due to invalid wpa_supplicant state.
  Error: Failed to connect to non-global ctrl_ifname: (nil) error: No such file or directory
  This was triggered from:

    systemctl status wpa_supplicant.service
    ● wpa_supplicant.service - WPA supplicant
      Loaded: bad-setting (Reason: Unit wpa_supplicant.service has a bad unit file setting.)
      Active: inactive (dead)
    systemd[1]: /usr/lib/systemd/system/wpa_supplicant.service:7: Invalid bus name, ignoring:
    systemd[1]: wpa_supplicant.service: Service is of type D-Bus but no D-Bus service name has been specified. Refusing.
  

• Subsequent scanning after a WiFi connection has been established was still unstable.
  Sometimes the wrong interface p2p-dev-wlan0 was used.

• Scan results were not always available, or only a few networks were retrieved

I wasn't able to fix everything and the proposed fixes for the Failed to connect to non-global ctrl_ifname error varied greatly. Therefore I decided to replace it with iw wlan0 scan.

Cosmetic changes:

• Fixed typos in web pages
• Suppress error messages in delete commands

@martonborzak @nklerk could you please test the setup and WiFi scanning on your hardware (I'm not sure who else has one)?
I don't want to make things worse since I don't have the real thing to test with...

[martonborzak]

Thanks @zehnm!
I'll test the setup (probably in a couple of days) and will report back.

[martonborzak]

Create dedicated project for webserver & shell scripts.

We have a separate repository for the web things, could you move the files there @zehnm ?
https://github.com/YIO-Remote/web-configurator

[zehnm]

Sure, I will get in contact with @nklerk once we are both online to coordinate.
We should probably also discuss a few things on how to proceed with 'system services' (currently mostly shell scripts).
It would be great to have the remote app running as non-root and take special care about all services requiring root access with a well defined API. I have an itch trying out Go ;-)