[workspace] Deprecate the ccd and fcl externals

[jwnimmer-tri]

Towards #17231. In the near future, we can adjust the build recipes for ..._internal to better suit our needs, but doing that here was too much churn. Here we just fork the rule largely unchanged, in support of deprecation.

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This change is 

[jwnimmer-tri]

+@rpoyner-tri for feature review, please.

Note that the commits are curated and in Reviewable as r1 and r2. Reviewing them one-at-a-time might be easiest.

[rpoyner-tri]

Reviewed 12 of 19 files at r1, 8 of 8 files at r2, all commit messages.
Reviewable status: needs at least two assigned reviewers, when planning a "properly curated" merge commit the PR must always be rebased onto latest master (waiting on @jwnimmer-tri)

[jwnimmer-tri]

+@sammy-tri for platform review, please. Note my comment above about reviewing commits one-at-a-time.

[sammy-tri]

Reviewed 12 of 19 files at r1, 8 of 8 files at r2, all commit messages.
Reviewable status: when planning a "properly curated" merge commit the PR must always be rebased onto latest master (waiting on @jwnimmer-tri)