feat: add new Subcircuit

[acl-cqc]

Part two of Luca's #1273, following #1288.

I've dropped the as_const_value, as_const_f64 and get_const_inputs methods for now as they are only used in a test, so all that will be in the third part

[codecov[bot]]

Codecov Report

:x: Patch coverage is 75.06329% with 197 lines in your changes missing coverage. Please review. :white_check_mark: Project coverage is 78.76%. Comparing base (c0d1236) to head (4aa5db0). :warning: Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
tket/src/subcircuit.rs	75.85%	155 Missing and 14 partials :warning:
tket/src/rewrite/strategy.rs	0.00%	17 Missing :warning:
tket/src/resource/scope.rs	85.71%	5 Missing and 2 partials :warning:
tket/src/resource/types.rs	0.00%	2 Missing :warning:
tket/src/rewrite/trace.rs	0.00%	1 Missing :warning:
tket/src/subcircuit/interval.rs	88.88%	0 Missing and 1 partial :warning:

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1289      +/-   ##
==========================================
- Coverage   79.53%   78.76%   -0.77%     
==========================================
  Files         160      161       +1     
  Lines       20571    21293     +722     
  Branches    19605    20327     +722     
==========================================
+ Hits        16361    16772     +411     
- Misses       3227     3527     +300     
- Partials      983      994      +11     

Flag	Coverage Δ
python	92.92% <ø> (ø)
qis-compiler	100.00% <ø> (ø)
rust	78.07% <75.06%> (-0.78%)	:arrow_down:

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[lmondada]

Hi Alan! Thank you so much, I'll have a look and answer tomorrow, hope that's okay!! Sorry for the delay