Add jpeg exif parser

[oh6hay]

One line description of pull request

Add a JPEG EXIF parser

Description:

Parses basic EXIF data from JPEG images. It seems introducing new dependencies isn't exactly encouraged due to possible license compatibility issues so I made a quick&dirty inline jpeg parser.

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:

• Automated checks (GitHub Actions, AppVeyor) pass
• No new new dependencies are required or l2tdevtools has been updated
• Reviewer assigned

[joachimmetz]

Thanks for the proposed changes, please take a look at the style guide https://plaso.readthedocs.io/en/latest/sources/developer/Style-guide.html and please change the PR to align with that style

[oh6hay]

hi @joachimmetz , the style guide is rather concise, could you kindly point towards any discrepancies?

[joachimmetz]

I'll take a closer look when time permits. In the meantime I recommend to have a look at similar parsers in Plaso. Unfortunately the style deviates from that at the moment, so merging the code might take a significant time (due to limited bandwidth on my end)

[oh6hay]

thanks @joachimmetz I'll have a look at other parsers. Are contributions to the style guide also welcome, to better define all aspects of the code and style conventions?

[joachimmetz]

Are contributions to the style guide also welcome, to better define all aspects of the code and style conventions?

They are. But realize though that some of the style decision are historical and we prefer to try to keep the code mostly in the same style. So making changes such as adoptions of f-strings or type hints takes time.