[REF] [EXPORT] [TLA] Update handling of input fields so that the mapping format is accepted.

[eileenmcnaughton]

Overview

Code cleanup on export - make it cleaner

Before

Confusing array format used

After

Sane array format used

Technical Details

Updates the export processor to accept the field mapping format from the civicrm_mapping_field table

The current situation is that a weird and wonderful format is used on the Mapping form quickform. This is converted to a sane format when saved to the civicrm_mapping_field table. However, the export processor currently expects the insane format - leading to complexity & lack of re-usablity.

This pr updates the workings of the export processor to use the sane format - as of this PR that are still received in the insane format but they are converted before they are actually used.

This sets us up to change the format received by the . function . & re-instate sanity (instate perhaps)

Comments

Although there is a lot of code in this PR it is very heavily tested. In fact every single change was made as part of stepping through a unit test because each changed line is specifically tested. We built up a lot of tests on this on the IM part of LeXIM over the last year

[civibot]

(Standard links)

• If this is your first pull-request for CiviCRM, please browse CONTRIBUTING.md for information about the development and testing processes.
• If you are reviewing this pull-request, you may wish to consult the test sites and the Review Standards (long template, short template).

[eileenmcnaughton]

test this please

[eileenmcnaughton]

test this please

[colemanw]

Great step forward @eileenmcnaughton!
Merging this based on code review & passing tests.