AT parser and gsm0710 muxer custom log category support

[avtolstoy]

Problem

Now that we have ESP32 support on Tracker, it's impossible to differentiate between NCP client / gsm0710 muxer logs that come from the cellular modem and ESP32.

Solution

Add instance-local custom log categories support for AT parser and gsm0710muxer.

This PR also fixes a bug in ChannelStream in waitEvent() timeout handling and makes sure that we have a single implementation of the gsm0710muxer (by having a common Stream base class that support eventGroup() method).

Steps to Test

Run the test app, watch logs. It should be easy to differentiate NCP/muxer logs that come from the modem and from ESP32.

Example App

SerialLogHandler dbg(LOG_LEVEL_ALL);

SYSTEM_MODE(SEMI_AUTOMATIC);

void setup() {
    waitUntil(Serial.isConnected);
    Particle.connect();
}

void loop() {
    WiFiAccessPoint results[5];
    WiFi.scan(results, sizeof(results) / sizeof(results[0]));
    auto sig = Cellular.RSSI();
    (void)sig;
    delay(5000);
}

Logs

0000034741 [ncp.at] TRACE: > AT+CCID
0000034743 [ncp.at] TRACE: < +CCID: XXXXXX
0000034743 [ncp.at] TRACE: < OK
0000034745 [ncp.at] TRACE: > AT+CGSN
0000034746 [ncp.at] TRACE: < YYYYYYY
0000034746 [ncp.at] TRACE: < OK
0000034753 [ncp.esp32.at] TRACE: > AT+MVER
0000034763 [ncp.esp32.at] TRACE: < 9
0000034763 [ncp.esp32.at] TRACE: < OK

0000029981 [mux] INFO: Starting GSM07.10 muxer
0000029981 [mux] INFO: Openning mux channel 0
0000029982 [mux] INFO: GSM07.10 muxer thread started
0000030083 [mux] INFO: Openning mux channel 1
0000022002 [ncp.esp32.mux] INFO: Starting GSM07.10 muxer
0000022004 [ncp.esp32.mux] INFO: Openning mux channel 0
0000022004 [ncp.esp32.mux] INFO: GSM07.10 muxer thread started
0000022010 [ncp.esp32.mux] INFO: Openning mux channel 1

References

• Custom instance-specific log category support gsm0710muxer#8

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Completeness

• User is totes amazing for contributing!
• Contributor has signed CLA (Info here)
• Problem and Solution clearly stated
• Run unit/integration/application tests on device
• Added documentation
• Added to CHANGELOG.md after merging (add links to docs and issues)