ContentRepository.fetchImage() FileData not ImageData (FINERACT-1201)

[vorburger]

This is an extension of #1425 for FINERACT-1201.

[vorburger]

Changing to Draft, because this currently fails like this:

DocumentTest > downloadFile() FAILED
    expected: 2080155
    but was : -1
        at org.apache.fineract.integrationtests.newstyle.DocumentTest.downloadFile(DocumentTest.java:87)

This is due to the test still running against https://www.fineract.dev - I REALLY need #1465 here to change it to run against localhost.

But let's first get #1425 reviewed and merged already.

[vorburger]

need #1465 here to change it to run against localhost. But let's first get #1425 reviewed and merged already.

I'll continue working on this after #1494 is merged.

[vorburger]

@ptuomola @vidakovic @percyashu @xurror @fynmanoj @avikganguly01 @vincent-fuchs @awasum any of you willing to review this, for FINERACT-1201? Once this is in, a few more such refactoring may be proposed, and ultimately I will then work on FINERACT-955 some day.

I'm reasonable confident that this won't break break any 🥰 the documents and images features, because in FINERACT-1218 I have contributed new test coverage for all this stuff (and since FINERACT-1209 those new tests DO actually run in our CI!), but of course careful human code review is always still a good idea... 😈

[percyashu]

LGTM!