HFD5: make tileshape optional

[sk1p]

Contributor Checklist:

• I have added myself to the creators.json file
• I have added a changelog entry for my contribution
• I have added/updated test cases

[codecov]

Codecov Report

Merging #578 into master will decrease coverage by 14.93%.
The diff coverage is 84.61%.

@@            Coverage Diff             @@
##           master    #578       +/-   ##
==========================================
- Coverage   73.84%   58.9%   -14.94%     
==========================================
  Files          89     208      +119     
  Lines        6622    8349     +1727     
  Branches      827    1073      +246     
==========================================
+ Hits         4890    4918       +28     
- Misses       1534    3230     +1696     
- Partials      198     201        +3

Impacted Files	Coverage Δ
src/libertem/io/dataset/hdf5.py	88.05% <84.61%> (-0.55%)	⬇️
src/libertem/win_tweaks.py	44.73% <0%> (ø)	⬆️
src/libertem/udf/blobfinder/correlation.py	98% <0%> (ø)	⬆️
src/libertem/io/utils.py	100% <0%> (ø)	⬆️
src/libertem/io/writers/base.py	98.38% <0%> (ø)	⬆️
src/libertem/io/dataset/k2is.py	26.92% <0%> (ø)	⬆️
client/src/widgets/Disk.tsx	0% <0%> (ø)
client/src/App.tsx	0% <0%> (ø)
...t/src/analysis/components/AnalysisLayoutTwoRes.tsx	0% <0%> (ø)
client/src/analysis/reducers.ts	0% <0%> (ø)
... and 115 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update ba17400...84efa49. Read the comment docs.