[WIP] add support for VEML7700

[szampardi]

Solved issues and/or description of the change

#726
...

Manual test

• OS and Version (Win/Mac/Linux):
• archlinuxarm 6.6.56-1-rpi (rpi0w 2)
• Adaptor(s) and/or driver(s):
• rpi
• i2c
  ...

Checklist

• The PR's target branch is 'hybridgroup:dev'
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes (e.g. by run make test_race)
• No linter errors exist locally (e.g. by run make fmt_check)
• I have performed a self-review of my own code

If this is a new driver or adaptor:

• I have added the name to the corresponding README.md
• I have added an example to see how to setup and use it
• I have checked or build at least my new example (e.g. by run make examples_check)

If this is a PR for release:

• The PR's target branch is 'hybridgroup:release'
• I have adjusted the CHANGELOG.md (or already prepared and will be merged as soon as possible)

[szampardi]

@gen2thomas the previous PR got auto-closed while I was trying to clean things up, should be fine now but I leave it up to the team to un-draft this

[gen2thomas]

@szampardi I have just added a comment in the previous PR. Thank you for driving this forward.