Porting bug fixes to stable for micro release

[Xarthisius]

This PR cherrypicks:

• Fix toggling 'public' parameter on a Tale. Fixes #121, #16 #124
• Allow to limit the number of concurrently running Instances per user #127
• Add narrative to Tales #131

for a bugfix release.

[codecov]

Codecov Report

Merging #162 into stable will increase coverage by 42.96%.
The diff coverage is 96.1%.

@@             Coverage Diff             @@
##           stable     #162       +/-   ##
===========================================
+ Coverage   38.68%   81.65%   +42.96%     
===========================================
  Files          18       18               
  Lines        1282     1330       +48     
===========================================
+ Hits          496     1086      +590     
+ Misses        786      244      -542

Impacted Files	Coverage Δ
server/schema/tale.py	100% <ø> (ø)	⬆️
server/models/instance.py	37.25% <ø> (+13.44%)	⬆️
server/constants.py	76.47% <100%> (+3.13%)	⬆️
server/rest/tale.py	87.75% <100%> (+43.79%)	⬆️
server/rest/instance.py	78.12% <88.88%> (+30.85%)	⬆️
server/__init__.py	88.33% <90%> (+46.22%)	⬆️
server/models/tale.py	89.39% <97.14%> (+63.93%)	⬆️
server/dataone_register.py	67.09% <0%> (+5.16%)	⬆️
... and 12 more

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