## Description
Create a wrapper struct that provides a `Fetch(ctx, name) (Stream, error)` function that always returns `ErrNotFound`. A future PR is going to expand the `RestoreCollection` interface to include that function and I wanted to reduce the amount of chaff that would come out of it
This PR just creates the wrapper and moves `ErrNotFound` from the kopia package to `data` package to avoid import cycles
## 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
- [x] 🌻 Feature
- [ ] 🐛 Bugfix
- [ ] 🗺️ Documentation
- [x] 🤖 Test
- [ ] 💻 CI/Deployment
- [ ] 🧹 Tech Debt/Cleanup
## Issue(s)
* #1944
## Test Plan
- [ ] 💪 Manual
- [x] ⚡ Unit test
- [ ] 💚 E2E
## Description
Split the collection interface into stuff used during backup and stuff used during restore. Does not change other code beyond fixing types
## 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#1944
## Test Plan
- [ ] 💪 Manual
- [x] ⚡ Unit test
- [x] 💚 E2E
## Does this PR need a docs update or release note?
- [x] ⛔ No
## Type of change
- [x] 🧹 Tech Debt/Cleanup
## Issue(s)
* #2329
## Test Plan
- [x] 💪 Manual
## Description
Begins updating operations/backup with the new
error handling procedures. For backwards
compatibility, errors are currently duplicated in
the old stats.Errs and the new Errors struct.
## Does this PR need a docs update or release note?
- [x] ⛔ No
## Type of change
- [x] 🧹 Tech Debt/Cleanup
## Issue(s)
* #1970
## Test Plan
- [x] ⚡ Unit test
- [x] 💚 E2E
## Description
Adds mocked unit tests for produceManifestsAnd-
Metadata. For cleanliness, moves that func, and
any funcs called within it, to their own file within operations
## Does this PR need a docs update or release note?
- [x] ⛔ No
## Type of change
- [x] 🤖 Test
## Issue(s)
* #2062
## Test Plan
- [x] ⚡ Unit test
