Automatic propagation of schema name as schema title

[ghik]

Closes #3447

At first, I tried a solution that would be as conservative as possible, i.e. adding a schema title only to coproduct case schemas. Ultimately, this doesn't seem practical because schemas listed in oneOf must be references (at least when discriminator field is used). This would require creating an additional, artificial named schema for every case, with only the title added, and it would probably look ugly in Swagger.

We should probably also be a bit careful with adding titles to all schemas unconditionally, as it may have some unintended side effects in Swagger (which I'm not aware of, so maybe I'm just being paranoic).

There's also always an option of making this behavior configurable with a flag.

[ghik]

I'm analyzing test failures and it seems that there's a conflict - TapirSchemaToJsonSchema also propagates schema names as titles, and it does it in a way that is incompatible with what I've added (i.e. it uses final, deduplicated schema names as titles). Not sure what to do about it.

[adamw]

@ghik let's drop that TapirSchemaToJsonSchema feature (along with the flag)

[adamw]

Thanks :)