Weldxfile tutorial + minor fixes

[marscher]

Changes

Added a tutorial describing the basic usage of the previously introduced WeldxFile class.

Fixes

• ASDF-2.8 removed the util function is_asdf_file, wrote a workaround.
• properly close file underlying handles, e.g. when opening a path via open.
• doctest in welding_schema
• get_schema_path uses constant SCHEMA_PATH

Checks

• updated CHANGELOG.md
• updated tests
• updated doc/
• update example/tutorial notebooks

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Codecov Report

Merging #355 (69feb83) into master (63c93ee) will increase coverage by 0.03%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #355      +/-   ##
==========================================
+ Coverage   96.87%   96.91%   +0.03%     
==========================================
  Files          87       87              
  Lines        5214     5214              
==========================================
+ Hits         5051     5053       +2     
+ Misses        163      161       -2     

Impacted Files	Coverage Δ
weldx/asdf/file.py	96.61% <0.00%> (+1.12%)	⬆️

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[marscher]

Seems like the update to Sphinx-4.0 on RTD makes the build failing.

[marscher]

reported import errors in sphinx upstream. Cref sphinx-doc/sphinx#9243

[marscher]

@CagtayFabry sorry for disturbing your writing silence. This is a blocker for ASDF-2.8 and I'd like to merge it quickly. I double checked the new tutorial and we can sort out problems with this later on. Or do you want me to open a separate PR just for the ASDF related fix(es)?

[CagtayFabry]

@CagtayFabry sorry for disturbing your writing silence. This is a blocker for ASDF-2.8 and I'd like to merge it quickly. I double checked the new tutorial and we can sort out problems with this later on. Or do you want me to open a separate PR just for the ASDF related fix(es)?

seems like I missed the 2.8 release
The changes needed for ASDF 2.8 are collected here #218 (probably a little outdated)
I guess we should update and merge quickly, maybe a minor weldx release just for ASDF 2.8 support as well
what do you think about merging this into #218 and updating that PR to fully support 2.8?

I will look into it #218 and this later tonight

[marscher]

I used a util function of ASDF in the new WeldxFile class, which got removed. As we did not yet release that, there is no demand to rush. But I'd like to merge both PRs soon to have a stable master branch. I can also perform a patch release to have the new features available. Unluckily sphinx seems to be broken (reported upstream). I will merge these on my behalf then. I also updated #218 already, so please do not ruin your precious free time ;)