Add support for SGP41

[martgras]

What does this implement/fix?

add support for SPG41 and SPG40. SGP41 supports all features of SGP40 but measures NOx as well.
The sensor type is autodetected.
Algorithm tuning option added.

Because spg41 adds NOx the new component is a multi-sensor component therefore a new configuration schema is required.
Therefore I decided to create a new component SPG4x supporting both sensors and mark the existing SPG40 component deprecated. Just changing the SGP40 component would break existing setups

Instead of copying the sensirion gas library code I'm now adding it as library. (https://github.com/Sensirion/arduino-gas-index-algorithm)
The only "problem" is esp-idf support. Because sensirion doesn't supply library.json the lib is considered arduino only. But actually it is framework agnostic. I submitted Sensirion/arduino-gas-index-algorithm#1 but in the meantime use my own fork at https://github.com/martgras/arduino-gas-index-algorithm .
Works like a charm with esp-idf

All other code is using the codebase from SGP40 by @SenexCrenshaw

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Other

Related issue or feature (if applicable): fixes

Pull request in esphome-docs with documentation (if applicable): esphome/esphome-docs#2016

Test Environment

• ESP32
• ESP32 IDF
• ESP8266

Example entry for config.yaml:

# Example config.yaml
  - platform: sgp4x
    voc:
      name: "VOC Index"
      id: sgp41_voc_index
      algorithm_tuning:
        index_offset: 100
        learning_time_offset_hours: 12
        learning_time_gain_hours: 12
        gating_max_duration_minutes: 180
        std_initial: 50
        gain_factor: 230
    nox:
      name: "NOx"
      algorithm_tuning:
        index_offset: 100
        learning_time_offset_hours: 12
        learning_time_gain_hours: 12
        gating_max_duration_minutes: 180
        std_initial: 50
        gain_factor: 230
        
    compensation:
      humidity_source: sht40_humidity
      temperature_source: sht40_temperature
    update_interval: ${updates}

Checklist:

• The code change is tested and works locally.
• Tests have been added to verify that the new code works (under tests/ folder).

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated in esphome-docs.

[probot-esphome]

Hey there @SenexCrenshaw, mind taking a look at this pull request as it has been labeled with an integration (sgp40) you are listed as a code owner for? Thanks!
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[probot-esphome]

Hey there @martgras,
Thanks for submitting this pull request! Can you add yourself as a codeowner for this integration? This way we can notify you if a bug report for this integration is reported.
In __init__.py of the integration, please add:

CODEOWNERS = ["@martgras"]

And run script/build_codeowners.py

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[jesserockz]

They will need to make another release on platformio for this to work. But for now you could point platformio.ini and cg.add_library to their repo.

[jesserockz]

Minor changes, otherwise looks fine.