Add parallel map facility in new task_utils

[netsettler]

• In exceptions:

  • New class MultiError

• In qa_utils:

  • New class Timer

• In misc_utils:

  • New generator function chunked

• New module task_utils:

  • New class Task
  • New class TaskManager
  • New function pmap
  • New function pmap_list
  • New function pmap_chunked

• Adjust expectations for environment hotseat in live ecosystem integration testing by tests/test_s3_utils.py

[coveralls]

Pull Request Test Coverage Report for Build 4724355857

• 158 of 162 (97.53%) changed or added relevant lines in 4 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.4%) to 74.982%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
dcicutils/exceptions.py	17	18	94.44%
dcicutils/misc_utils.py	12	13	92.31%
dcicutils/qa_utils.py	21	22	95.45%
dcicutils/task_utils.py	108	109	99.08%
<!--	Total:	158	162	97.53%	-->

Totals
Change from base Build 4690904380:	0.4%
Covered Lines:	6336
Relevant Lines:	8450

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💛 - Coveralls