use 2.13-style collections library syntax in json-api

[S11001001]

Preparing for Scala 2.13 by removing some constructs no longer present there, replacing them with existing portable constructs or those provided by scala-collection-compat, as @leo-da suggested. Currently included:

• For single-operation breakOut, we use .view.op(...).toX, with variations:
  • where view causes an Any warning, we use iterator instead
  • where there are multiple operations, we use iterator instead
  • where there is no toX, we use to(X) instead, by importing scala.collection.compat._
• For to[X], we use toX or to(X), depending on what is available
  • this includes the hacky test mode for doobie, for which the CBF hack works equally well, hence the presence of to(List)

Those of the changes above that didn't require scala-collection-compat have also been made in the daml-lf tree.

Fixes #5874.

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[leo-da]

looks good, but we need to make sure the changes do not affect performance, we touched interpreter and data.transaction

[remyhaemmerle-da]

Looks good.

[ghost]

Noice.

[S11001001]

As discussed, these changes lay outside the critical path in question.