feat: HUGR extension for global variables

[maximilianruesch]

A HUGR extension for setting global variables. Currently only a single operation is defined: The swap operation for swapping the global state with a new value, returning the old value. Allows the string name of the state variable to be specified.

[codecov]

Codecov Report

❌ Patch coverage is 77.61194% with 30 lines in your changes missing coverage. Please review.
✅ Project coverage is 83.77%. Comparing base (c290814) to head (65b0ab7).
⚠️ Report is 6 commits behind head on main.

Files with missing lines	Patch %	Lines
tket-qsystem/src/extension/globals.rs	69.69%	20 Missing ⚠️
tket-qsystem/src/llvm/globals.rs	82.50%	1 Missing and 6 partials ⚠️
qis-compiler/rust/lib.rs	0.00%	2 Missing ⚠️
tket-qsystem/src/bin/tket-qsystem.rs	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1530      +/-   ##
==========================================
- Coverage   83.83%   83.77%   -0.06%     
==========================================
  Files         187      191       +4     
  Lines       28956    29166     +210     
  Branches    27877    28037     +160     
==========================================
+ Hits        24274    24434     +160     
- Misses       3521     3564      +43     
- Partials     1161     1168       +7     

Flag	Coverage Δ
python	92.50% <100.00%> (+0.16%)	⬆️
qis-compiler	91.66% <ø> (ø)
rust	83.42% <72.47%> (-0.08%)	⬇️

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.