Add PLS2-L-V6 Level Transmitter with payload decoder

[ellenex]

Summary

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Changes

This PR adds a new device model from Ellenex:

Device files added:

pls2-l-v6.yaml
pls2-l-v6-codec.yaml
pls2-l-v6-profile.yaml
pls2-l-v6.js
Features:

LoRaWAN MAC 1.0.3, supports OTAA
Sensor: Level
Battery: 3.6V Lithium C
Class A device
Profiles for AS923, EU863-870, US902-928, AU915-928 regions
Payload decoder included (CBOR format)
Examples added for testing
Testing performed:

Uplink decoder validated locally
Downlink encoder tested with example commands
Prettier formatting applied and validated
Please review and merge if everything is okay.

Checklist for Reviewers

• Title and description should be descriptive (Not just a serial number for example).
• profileIDs should not be vendorID and should be a unique value for every profile.
• All devices should be listed in the vendor's index.yaml file.
• Firmware versions can not be changed.
• At least 1 image per device and should be transparent.

Notes for Reviewers

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Release Notes

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