Catch exceptions when creating/deleting clusters

[ehoelzl]

Closes #94

[codecov]

Codecov Report

Merging #276 into develop will increase coverage by 0.00%.
The diff coverage is 37.50%.

@@           Coverage Diff            @@
##           develop     #276   +/-   ##
========================================
  Coverage    26.08%   26.08%           
========================================
  Files          100      100           
  Lines         6203     6217   +14     
========================================
+ Hits          1618     1622    +4     
- Misses        4585     4595   +10     

Impacted Files	Coverage Δ
mlbench_core/cli/gcloud_utils.py	52.94% <37.50%> (-3.88%)	⬇️

---

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 6bb8e06...583ffe3. Read the comment docs.