refactor: one place for Key Vault collections and paging in the providers

- ObjectType.Collection names a type's segment in Key Vault URLs and links (secrets, keys, certificates), instead of four copies in ref, azure and fake.
- Azure lists through one pager helper instead of eight hand-written page loops; Value is VersionedValue without the version, rather than the two calling each other.
- Databricks' Key Vault fallback check lives in fallbackVault.
- The repo provider reads .lazysecrets.yaml in one place, builds plain and sops objects in one loop, and parses a file's sops metadata from the bytes Objects already read.

internal/share/rules.go

@@ -48,7 +48,11 @@ func (r Rules) Check(key []byte) error {
 		needs = append(needs, fmt.Sprintf("%d (minLength)", r.MinLength))
 	}
 	if kinds < r.MinClasses {
-		has = append(has, fmt.Sprintf("%d %s of character", kinds, map[bool]string{true: "kind", false: "kinds"}[kinds == 1]))
+		kind := "kinds"
+		if kinds == 1 {
+			kind = "kind"
+		}
+		has = append(has, fmt.Sprintf("%d %s of character", kinds, kind))
 		needs = append(needs, fmt.Sprintf("%d of lowercase, uppercase, digits and symbols (minClasses)", r.MinClasses))
 	}
 	if len(has) == 0 {