Remove dead code from refactoring Resource struct (#2093)

## Description

Now unused code

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

- [ ] ✅ Yes, it's included
- [ ] 🕐 Yes, but in a later PR
- [x] ⛔ No 

## Type of change

- [ ] 🌻 Feature
- [ ] 🐛 Bugfix
- [ ] 🗺️ Documentation
- [ ] 🤖 Test
- [ ] 💻 CI/Deployment
- [x] 🧹 Tech Debt/Cleanup

## Issue(s)

* closes #1916 

## Test Plan

- [ ] 💪 Manual
- [x] ⚡ Unit test
- [x] 💚 E2E

src/internal/kopia/snapshot_manager.go

@@ -66,30 +66,6 @@ type snapshotManager interface {
 	LoadSnapshots(ctx context.Context, ids []manifest.ID) ([]*snapshot.Manifest, error)
 }
 
-type OwnersCats struct {
-	ResourceOwners map[string]struct{}
-	ServiceCats    map[string]ServiceCat
-}
-
-type ServiceCat struct {
-	Service  path.ServiceType
-	Category path.CategoryType
-}
-
-// MakeServiceCat produces the expected OwnersCats.ServiceCats key from a
-// path service and path category, as well as the ServiceCat value.
-func MakeServiceCat(s path.ServiceType, c path.CategoryType) (string, ServiceCat) {
-	return serviceCatString(s, c), ServiceCat{s, c}
-}
-
-// TODO(ashmrtn): Remove in a future PR.
-//
-//nolint:unused
-//lint:ignore U1000 will be removed in future PR.
-func serviceCatTag(p path.Path) string {
-	return serviceCatString(p.Service(), p.Category())
-}
-
 func serviceCatString(s path.ServiceType, c path.CategoryType) string {
 	return s.String() + c.String()
 }
@@ -104,33 +80,6 @@ func makeTagKV(k string) (string, string) {
 	return userTagPrefix + k, defaultTagValue
 }
 
-// tagsFromStrings returns a map[string]string with tags for all ownersCats
-// passed in. Currently uses placeholder values for each tag because there can
-// be multiple instances of resource owners and categories in a single snapshot.
-// TODO(ashmrtn): Remove in future PR.
-//
-//nolint:unused
-//lint:ignore U1000 will be removed in future PR.
-func tagsFromStrings(oc *OwnersCats) map[string]string {
-	if oc == nil {
-		return map[string]string{}
-	}
-
-	res := make(map[string]string, len(oc.ServiceCats)+len(oc.ResourceOwners))
-
-	for k := range oc.ServiceCats {
-		tk, tv := makeTagKV(k)
-		res[tk] = tv
-	}
-
-	for k := range oc.ResourceOwners {
-		tk, tv := makeTagKV(k)
-		res[tk] = tv
-	}
-
-	return res
-}
-
 // getLastIdx searches for manifests contained in both foundMans and metas
 // and returns the most recent complete manifest index and the manifest it
 // corresponds to. If no complete manifest is in both lists returns nil, -1.