Upgrades ember-resources to v7.

It also upgrades the dependencies (if outdated) to their new minimum version.
These upgrades should probably happen as separate PRs though.

Implementation of the codemod here: NullVoxPopuli/ember-resources#1147

Here are the breaking changes in v6:

• https://github.com/NullVoxPopuli/ember-resources/releases/tag/ember-resources%406.0.0
  • most of the changes here do not affect cardstack because most of the changes are from utilities that cardstack doesn't import/use (more on this in v7)

Here are the breaking changes in v7:

• https://github.com/NullVoxPopuli/ember-resources/releases/tag/v7.0.0-ember-resources
  • All utilities moved to reactiveweb, documentation here: https://reactive.nullvoxpopuli.com/
  • This mostly doesn't affect cardstack, because cardstack does not use any of the utilities
  • Additionally, the Resource class has moved to a separate package, https://github.com/NullVoxPopuli/ember-modify-based-class-resource/
    • This is to align with the ember ecosystem, and the desire to move away from modify() hooks -- as they are a sort of backdoor effect, which we don't want to encourage -- instead folks should rely on more data derivation patterns

Possible remaining steps to do:

• find peer-consumer references and update them