webp image support

[SchrodingersGat]

Currently the docker install does not support webp images, while some bare-metal installs do.

Given the popularity of webp images, especially among electronics distributors, this PR adds (and tests) support for webp

Closes #2988

[matmair]

Nice one - should catch some docker problems sooner

[SchrodingersGat]

@matmair interestingly some tests have already failed when building under docker

The environment variables test is failing. Any thoughts on how to address this one?

[matmair]

@SchrodingersGat could you merge in recent changes? The import should work in alpines version of python3

[SchrodingersGat]

Annoyingly this EnvironmentVarGuard import issue is still hanging around. I can't import test.support in any version of python I try.. Any ideas?

[matmair]

@SchrodingersGat I will have a look at that.

[matmair]

@SchrodingersGat working on this on my fork:
https://github.com/matmair/inventree/tree/webp-support will ping you once it runs.

[matmair]

@SchrodingersGat can you try merging my branch into yours?

[SchrodingersGat]

@matmair still no luck. What version of python are you running?

[matmair]

3.8 - but this function was introduced in 3.2 . I do not get it

[SchrodingersGat]

Huh, it appears that the inventree-python library is installing a library "test" into the venv which is overriding the default test package install:

[SchrodingersGat]

Well progress, of sorts.. I've fixed the inventree-python issue, but now getting a new error message:

[matmair]

@SchrodingersGat python packages/imports are sometimes... flawed

[SchrodingersGat]

@matmair would you be ok with changing this test to not use test.support module? It is not recommended for public consumption

Maybe something like this?

[matmair]

@SchrodingersGat I was not aware of this option. Seems like a good solution.

[matmair]

@SchrodingersGat please merge again from my branch

[SchrodingersGat]

Let's see how we go this time