distribute operations integration tests (#3706)

Moves operations integration backup tests into a
subpackage, and slices up the test folder into
multiple, service specific folders.

No logic changes, only code copy-pasting and
renaming.

---

#### Does this PR need a docs update or release note?

- [x] ⛔ No

#### Type of change

- [x] 🤖 Supportability/Tests

#### Test Plan

- [x] 💚 E2E

src/internal/operations/backup.go

@@ -45,12 +45,12 @@ type BackupOperation struct {
 	Selectors selectors.Selector `json:"selectors"`
 	Version   string             `json:"version"`
 
-	// backupVersion ONLY controls the value that gets persisted to the
+	// BackupVersion ONLY controls the value that gets persisted to the
 	// backup model after operation.  It does NOT modify the operation behavior
 	// to match the version.  Its inclusion here is, unfortunately, purely to
 	// facilitate integration testing that requires a certain backup version, and
 	// should be removed when we have a more controlled workaround.
-	backupVersion int
+	BackupVersion int
 
 	account account.Account
 	bp      inject.BackupProducer
@@ -83,7 +83,7 @@ func NewBackupOperation(
 		ResourceOwner: owner,
 		Selectors:     selector,
 		Version:       "v0",
-		backupVersion: version.Backup,
+		BackupVersion: version.Backup,
 		account:       acct,
 		incremental:   useIncrementalBackup(selector, opts),
 		bp:            bp,
@@ -258,7 +258,7 @@ func (op *BackupOperation) Run(ctx context.Context) (err error) {
 		sstore,
 		opStats.k.SnapshotID,
 		op.Results.BackupID,
-		op.backupVersion,
+		op.BackupVersion,
 		deets.Details())
 	if err != nil {
 		op.Errors.Fail(clues.Wrap(err, "persisting backup"))