Updated Google Timeline Import script

[aaronspruit]

After getting owntracks setup in my own environment, I stumbled upon the existing Timeline Import script. Unfortunately, it no longer works due to changes in the jason google provides.

As that repo is now deprecated, and seeing that the GPX import script landed here, I figured I'd open a PR for this too.

Changes to the script include:

• fixes to parse the new timestamp key in the timeline json so that the message 'tst' key is properly updated
• made the trackerID a user-supplied argument instead of being hardcoded

[jpmens]

Thank you, @aaronspruit, I have merged your contribution.

[Korenchkin]

not an author of this,but this aproach seems spot-on what is needed,and solves my problems the same way-too large file-crash,add more ram-works,but skips some points: https://www.technowizardry.net/2024/01/migrating-from-google-location-history-to-owntracks/
could someone make this official?