A lazy method to construct QobjEvo

[ytdHuang]

Checklist

Thank you for contributing to QuantumToolbox.jl! Please make sure you have finished the following tasks before opening the PR.

• Please read Contributor Covenant Code of Conduct
• Any code changes were done in a way that does not break public API
• Appropriate tests were added and tested locally by running: make test.
• Any code changes should be julia formatted by running: make format.
• All documents (in docs/ folder) related to code changes were updated and able to build locally by running make docs.

Request for a review after you have completed all the tasks. If you have not finished them all, you can also open a Draft Pull Request to let the others know this on-going work.

Description

Summary of this PR:

• Add a lazy method to construct QobjEvo
• make mcsolveProblem accept H_eff::AbstractQuantumObject to fix extra ScalarOperator for time-independent mcsolve. This breaks many things in dynamical solvers
• improve runtests to make sure time-independent problems are MatrixOperator

Related issues or PRs

Please mention the related issues or PRs here. If the PR fixes an issue, use the keyword close/closes/closed/fix/fixes/fixed/resolve/resolves/resolved followed by the issue id, e.g. fix #[id]
close #281

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 93.62%. Comparing base (380d017) to head (d507107).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #282      +/-   ##
==========================================
- Coverage   94.16%   93.62%   -0.54%     
==========================================
  Files          32       32              
  Lines        2468     2463       -5     
==========================================
- Hits         2324     2306      -18     
- Misses        144      157      +13     

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