Install extra requirements for thumbor

[NotWoods]

Fixes #160

numpy 2 was getting installed rather than numpy 1, so I'm trying to tweak the requirements file to fix that. thumbor lists numpy in it's extra_require list, so I'm trying to opt into that using the [tag] syntax.

• Syntax is from https://setuptools.pypa.io/en/latest/userguide/dependency_management.html
• thumbor's extra requirements is listed in https://github.com/thumbor/thumbor/blob/252c5b10ff4766b8a09e0a017a11cb9912bf557a/setup.py#L161-L165

This also lets us move the list of extra requirements (cairosvg, pycurl, pillow-avif-plugin) from the requirements file to thumbor's setup.py. We now also pull in pillow-heif to support heif output.

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I'm not super familiar with pip and dockerfiles so I might've gotten something wrong here. Please help me test it out!

[gingerlime]

Thanks so much. Looks much cleaner as well 👍 Merged via #162