Add DJI DAT Parser

[arilimata]

One line description of pull request

Add parser for DAT files by DJI log DAT file

Description:

Add parser for decrypting and parsing .DAT files generated by DJI drone controllers and onboard flight systems.

Notes:

All contributions to Plaso undergo code review.
This makes sure that the code has appropriate test coverage and conforms to the
Plaso style guide.

One of the maintainers will examine your code, and may request changes. Check off the items below in
order, and then a maintainer will review your code.

Checklist:

• No new new dependencies are required or l2tdevtools has been updated.
• Test data has a Plaso compatible license. If the test data was not authored by you (the contributor), make sure to mention its orginal source in ACKNOWLEDGEMENTS.
• Reviewer assigned.
• Automated checks (GitHub Actions, AppVeyor) pass.

[joachimmetz]

@arilimata please rebase with current HEAD