add ability to omit join__ directives from being cloned

[clenfest]

For very large graphs cloning types with lots of join directives can be expensive. Since these directives will not be used in the Schema that is cloned for toAPISchema(), add the ability to optionally omit them

[changeset-bot[bot]]

⚠️ No Changeset found

Latest commit: 6adc87132c977cca8bd26a196cf507063353ec8a

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR

[netlify[bot]]

✅ Deploy Preview for apollo-federation-docs canceled.

Name	Link
🔨 Latest commit	c3a511d0ad01f282623d71cee8cd7b90f856ccf8
🔍 Latest deploy log	https://app.netlify.com/sites/apollo-federation-docs/deploys/667df9ff8e7f2d00087e669b

[codesandbox-ci[bot]]

This pull request is automatically built and testable in CodeSandbox.

To see build info of the built libraries, click here or the icon next to each commit SHA.