feat: add tls support

[sholdee]

No description provided.

[miaucl]

Hey, thanks for the PR. To review this, I will have to setup my own mqtt with tls. This might take a while, especially over the holidays, your PR is not forgotten :)

[gms1]

this works for me!

tested using

pipx install git+https://github.com/sholdee/linux2mqtt.git@add-tls --force
pipx runpip linux2mqtt install "psutil<6.0.0"

NOTE: ca must have keyUsage set to e.g critical, digitalSignature, cRLSign, keyCertSign
otherwise it will fail with: "ssl.SSLCertVerificationError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: CA cert does not include key usage extension (_ssl.c:1029) "