Add support for ProvidePasswordCallback to EFCore.PG

[williamdenton]

This repo has not been updated to use a new enough version (>4.1) of Npgsql yet for this to compile. I didn't want to charge ahead and do that as it seems outside the scope of this PR to do that upgrade, but it is required for this PR as it uses the new member ProvidePasswordCallback on NpgsqlConnection which was added in npgsql/npgsql#2502

[austindrenski]

I didn't want to charge ahead and do that as it seems outside the scope of this PR to do that upgrade, but it is required for this PR

Appreciate the narrow approach you've taken, but feel free to add the upgrade as a separate (prepended) commit so that the CI tests build during review.

We can always drop or cherry-pick around it when it's time to merge.

[roji]

Looks good overall, thanks for plumbing this through the EF Core provider.

Missing: You also need to make the appropriate changes in NpgsqlOptionsExtension.cs.PopulateDebugInfo

[williamdenton]

forced pushed the change to keep it easy to remove the 4.1 upgrade commit later

[williamdenton]

Rebased on preview 7

[williamdenton]

Looks like I need to fix this up more. I'm away for the next week then will get this sorted

[roji]

Thanks for this extra work @williamdenton, take your time.

[williamdenton]

@roji I've rebased on latest dev and this looks like its passing now that npgsql 4.1 is referenced

[roji]

LGTM, could you please rebase on the latest dev? I'm seeing some conflicts locally (which for some reason don't appear on github).

[williamdenton]

@roji rebased on aa6809e

[roji]

Remerged via a2180f0 - the original merge somehow did not occur?