Update WiFiScan example to show more useful data

[Rotzbua]

Description of Change

Update WiFiScan example to show more useful data.

• Add channel to output.
• Add type of encryption to output.
• Format output as table.
• Update outdated example description.

Since this example is part of the Arduino library I avoided to add IDF specific code.

Tests scenarios

• Tested on ESP32-C3 Board.
• Let CI compile.

Related links

Closes #7377

[VojtechBartoska]

@P-R-O-C-H-Y & @PilnyTomas Please help with the review.

[Xylopyrographer]

Suggest changing this to accommodate 32 character SSID maximum to:

Serial.println( " # | SSID                             | RSSI | CH | Encryption" );

Suggest adding the following after the above to "pretty up" the output table:
Serial.println( "---------------------------------------------------------------" );

[me-no-dev]

I will also suggest to add BSSID column to differentiate between APs with the same SSID

[Rotzbua]

@me-no-dev Should I increase the column size? The limitation was on purpose because it is easier to read a table row without a huge space between the columns. Most SSIDs were shorter than 15 chars on my test setup.

[mrengineer7777]

Since this is an example, I recommend printing the whole SSID. I agree a shorter SSID field looks better, but that can be customized for each application. This is the header I use for printing WiFi list (debug use only):

Serial.println(" #                             SSID  BSSID              RSSI  Ch  Authmode  Rate" );
Serial.println("-----------------------------------------------------------------------------------" );

I print the full SSID with sprintf(ptr, "%32s ", AP->ssid[0] != 0 ? (const char *)AP->ssid : "<hidden>");.

[PilnyTomas]

I vote for accommodating the longer RSSIs
This is what it looks like for 32-char RSSI

4 networks found
Nr | SSID            | RSSI | CH | Encryption
 1 | Foo             |  -34 |  4 | WPA2
 2 | 0123456789abcdef0123456789abcdef |  -34 | 11 | WPA2
 3 | Bar             |  -76 |  4 | WPA2
 4 | 42              |  -87 |  4 | WPA2

Tip - use std::string (variable_white_space_length, ' ') to pad table dynamically - see it used here

[mrengineer7777]

Tip - use std::string (variable_white_space_length, ' ') to pad table dynamically

That's interesting. IMHO the field width specifier in printf/sprintf is even easier to use.
https://www.tutorialspoint.com/c_standard_library/c_function_sprintf.htm
e.g.
sprintf(buf, "%3u", 42)
sprintf(buf, "%32s", ssid.c_str())
sprintf(buf, "%-32s", ssid.c_str())
sprintf(buf, "%*s", width, ssid.c_str()) //I have not tried the variable width format specifier

need to merge