VP-2349: Refactor VirtoCommerce.AvalaraTax module to apply setting values immediately

[eMazeika]

https://virtocommerce.atlassian.net/browse/VP-2349

[vc-ci]

SonarQube analysis reported 7 issues

Note: The following issues were found on lines that were not modified in the pull request. Because these issues can't be reported as line comments, they are summarized here:

1. OrdersSynchronizationJob.cs#L61: Either remove or fill this block of code.
2. AvaTaxController.cs#L63: 'System.Exception' should not be thrown by user code.
3. AvaTaxController.cs#L73: 'System.Exception' should not be thrown by user code.
4. AvaTaxController.cs#L87: 'System.Exception' should not be thrown by user code.
5. AvaTaxController.cs#L93: 'System.Exception' should not be thrown by user code.
6. AvaTaxController.cs#L100: 'System.Exception' should not be thrown by user code.
7. Module.cs#L37: Remove the field '_appBuilder' and declare it as a local variable in the relevant methods.

The base branch was changed.

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