Compact MPS/MPO printing

[mtfishman]

Revamp of #772, closes #64. Related to ITensor/ITensors.jl#1680.

[codecov]

Codecov Report

❌ Patch coverage is 88.88889% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 90.31%. Comparing base (b94c4bc) to head (29c50bf).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/abstractmps.jl	88.88%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #166      +/-   ##
==========================================
+ Coverage   90.29%   90.31%   +0.02%     
==========================================
  Files          54       54              
  Lines        3605     3604       -1     
==========================================
  Hits         3255     3255              
+ Misses        350      349       -1     

Flag	Coverage Δ
docs	17.98% <ø> (-0.03%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.