Consider supporting deleting database snapshot files of old migrations

[nphmuller]

Since our application is slowly accumulating a lot of database migrations, compiling is starting to take a while (compiling + Roslyn analyzers).

The biggest part of compilation is spend on database snapshots from old migrations. So it would be great if they could be deleted, if I don't want to support reverting those migrations.

See @bricelam 's answer on StackOverflow: https://stackoverflow.com/a/47060795/5473409
I stumbled upon this answer when trying to: Find a recommended way to clean old EFCore migrations

Further technical details

EF Core version: 2.0.0-2.2.4
Database Provider: Microsoft.EntityFrameworkCore.SqlServer
Operating system: Win 10 (1903)
IDE: VS 2019 16.1.3

[ajcvickers]

@nphmuller This is basically tracked by #2174 which is about squashing migrations. Until that feature is implemented, it should be possible to workaround this by manually deleting or scripting deletions, as Brice says in his post.