Make the parser compile for Windows and Linux machines

[PolarGoose]

Description

I have tried the proposal from @matthijskooijman and managed to make the parser compile and work on Windows and Linux machines. I have only tested it on Windows, but there shouldn't be any problems with Linux.
This can be very beneficial because the parser can be used on Raspberry Pi and other Linux-based embedded boards, for example.

Content of the pull request

• Replace the usage of Arduino String with std::string
• Add a unit test project to test the parser

[LarsStegman]

This is great! When this is merged, ESPHome can be updated to use the new version. This should finally fix this issue: esphome/issues#3982

[PolarGoose]

@LarsStegman,
Nice, then there is even a real use case for this already.
From the issue that you have mentioned I see that the ESP Home uses the glmnet/Dsmr fork of this library. It means that we will also need to coordinate with the fork owner about merging these changes into his fork.
I would like to chat with you about it, could you please contact me to my [email protected]?

[glmnet]

Thanks! I will like this PR be tested in ESPHome before pushing a version

[LarsStegman]

@PolarGoose will you continue the work on this PR?

[PolarGoose]

I want to finish this pull request. However, I don't know much about ESPHome and how it can be tested.
@LarsStegman and @glmnet, can you test these changes on ESPHome after I finish them?

[LarsStegman]

I have no idea how to do that yet, but I can try.

[PolarGoose]

I have no idea how to do that yet, but I can try.

@glmnet, could you please help us with the testing when the pull request is finished?