feature/urdd timing strategy

[nbronn]

Created a new DD pass URDDSequenceStrategy that inherits from PadDynamicalDecoupling, but only inserts a certainumber num_pulses of the URDD sequence when the delay time is greater than specified time min_delay_time. Also includes a helper function urdd_strategy_passes which constructs the list of passes for doing this sequentially, most likely in decreasing order in both num_pulses and min_delay_time so that larger blocks of delay times are taken up by longer sequences.

[coveralls]

Pull Request Test Coverage Report for Build 5693648313

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 14 of 109 (12.84%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-2.7%) to 82.606%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
qiskit_research/utils/dynamical_decoupling.py	14	109	12.84%

Totals
Change from base Build 5524177036:	-2.7%
Covered Lines:	2441
Relevant Lines:	2955

---

💛 - Coveralls