Never make a credential only a person can give, and give it once per provider (hq issue 164, ADR 0337)

A Servarr app's API key, an indexer's key and a downloader's password are values the provider's
software holds; the pair path made a random value for every consumer of them, sealed it to both ends
and reported success, and the provider refused it. An offer may now say `"credential": {"issued-by":
"outside"}`: SecretFor never makes a value for it, the plan reads such a pair as given or not given
and sends the consumer no credential file until a person gives it, without refusing its machine;
remakeShared and SharedSecretFor never make a provider's own secret issued outside either.
`secret accept <provider's node> <provider module> <provision>` seals one value to every consumer that
binds the provision from that provider, the provider and the operator, under one generation; the
per-pair form is refused for such a provision, and rotate names the accept. A consumer may wait for a
provision's credential: the controller excuses the wait only when the store bears it out, and its
needs-operator condition names the one accept line.

Adds the replay of issue 164 (TestReplay164), written with only what the controller had before.

testdata/store-tests

@@ -46,3 +46,8 @@
 ./cmd/mesh-controller TestReplay239AModuleNameIsNotTakenOverByAnotherRepository
 ./cmd/mesh-controller TestAWalkThatMovedNothingSaysWhichModulesMatchedWhatRuns
 ./cmd/mesh-controller TestReplay614ANewSDKPlansTheToolchainAndThenItsBundles
+./internal/inventory TestACredentialIssuedOutsideIsNeverMade
+./internal/inventory TestOneAcceptForAProviderIsSealedToEveryConsumer
+./internal/inventory TestASharedOwnSecretIssuedOutsideIsNeverMade
+./cmd/mesh-controller TestOneAcceptForAProviderIsPlacedForEveryConsumer
+./cmd/mesh-controller TestReplay164