Disabled threads for the wrappers, added an option to enable them. Refactored the function, added docs

Now, wrappers admits %Placeholders%

Fixes check: "on_submission" for wrappers and total_jobs when set at job_level

Closes #1255

See merge request !414

Fix "previous" when there is only a single job

See merge request !415

Calendar splits - rebased

Closes #1158

See merge request !407

Get rid of DeprecationWarning: pkg_resources is deprecated as an API

See merge request !416

This reverts commit a4619629.

Fix trace when exception as e is not an AutosubmitCritical or AutosubmitError

update version

Fix trace when exception as e is not an AutosubmitCritical or AutosubmitError

update version

Fix trace when exception as e is not an AutosubmitCritical or AutosubmitError