Use constructor to create IATEntryDetails when parsing IAT batches

[ckbaum]

• Use NewIATEntryDetail() (rather than new(IATEntryDetail)) to create IAT entry details when parsing a file; this sets a couple important defaults including Category, which is currently blank for all parsed IAT forwards.
• Strip extra whitespace by default when parsing account numbers of IAT entries, to match the behavior of parsed account numbers for other entry details (we can leave this change off if it feels potentially disruptive.)

[codecov-commenter]

Codecov Report

Merging #1357 (670833c) into master (e3059e8) will increase coverage by 0.10%. Report is 82 commits behind head on master. The diff coverage is 91.11%.

:exclamation: Current head 670833c differs from pull request most recent head 8eee7d7. Consider uploading reports for the commit 8eee7d7 to get more accurate results

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Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #1357 +/- ## ========================================== + Coverage 88.33% 88.43% +0.10% ========================================== Files 75 75 Lines 7227 7767 +540 ========================================== + Hits 6384 6869 +485 - Misses 501 541 +40 - Partials 342 357 +15 ```