Improve display of standard name mapping creation and editing form

[David Platten]

No description provided.

[David Platten]

Made table the full width of the div by setting table class to table. Added human-readable modality to text at top of page [skip ci]. Refs issue #980

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[David Platten]

Updated the changes file [skip ci]. Refs issue #980

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[Ed McDonagh]

Merged in issue980improveStandardNameFormAppearance (pull request #562)

Fixes #980

Approved-by: Ed McDonagh

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