Teach API change review scripts to split on Qt module rather than git module

janihe heroically split by hand the multi-Qt-module git modules' 6.3 API change reviews into separate commits for each Qt module. It should be possible to automate this.

The sync-filter-api-headers script currently just mindlessly emits a list of files that are relevant to API. At the cost of teaching it to respond to some command-line arguments, we can get it to give us more helpful information, so that we can partition the source tree between distinct modules, doing the needed change-determination using that.
It may be as simple as having it change how it produces output, so that it breaks up the file list it currently produces with "end of a module" marker lines, in response to which the system pauses from reading file-names to make a module-specific commit.

The api-review-gen module would then change how it uses that to scan sync.profile and produce a series of commits, one per Qt module, instead of one commit that combines them.
Neither resetboring.py nor all-api-modules would need any change.

david.skoland's fullrun/ scripts would presumably also need some change; I leave it to him to consider how to do that.