re-add the Encoder and Decoder APIs

We're a semver v1, so we can't remove exposed APIs unless we bump to
v2+. Bumping the major version to just rename two APIs seems a bit
overkill; keeping the old ones around and deprecating them is much
easier.

This partially reverts commit b8473079.
3 jobs for up/v1.2.0 in 0 seconds (queued for 95 minutes and 59 seconds)
Status Job ID Name Coverage
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code_quality

failed #2634
test

 
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