Unclear if this is precisely the path we want to take to handle possible
partial repo initialization so feel free to leave suggestions if a
different behavior would be better
Update the repo init logic to continue if the repo is marked as already existing. If it already exists then the process will try to update persistent config info in the repo. If the repo already exists but some connection credential is incorrect then stack errors such that both the reason for the connect failure and the fact that the repo already exists are both visible.
Manually tested attempting to initialize a repo that was already
initialized but using a different passphrase and got the output:
```text
Error: initializing repository: a repository was already initialized with that configuration: connecting to kopia repo: unable to create format manager: invalid repository password: repo already exists: repository already initialized
exit status 1
```
Attempting to initialize a repo again using the same passphrase resulted
in a success message with no errors reported
Unfortunately I can't really add unit tests to ensure the config ends up
the way we expect because I have no way to trigger an error partway through
kopia's init logic (or even just after it) without some non-trivial code
refactoring
---
#### Does this PR need a docs update or release note?
- [x] ✅ Yes, it's included
- [ ] 🕐 Yes, but in a later PR
- [ ] ⛔ No
#### Type of change
- [ ] 🌻 Feature
- [x] 🐛 Bugfix
- [ ] 🗺️ Documentation
- [ ] 🤖 Supportability/Tests
- [ ] 💻 CI/Deployment
- [ ] 🧹 Tech Debt/Cleanup
#### Test Plan
- [x] 💪 Manual
- [x] ⚡ Unit test
- [ ] 💚 E2E
<!-- PR description-->
New commands to initialize & connect to a repo on local or network attached storage.
* `repo init filesystem --path /tmp/repo`
* `repo connect filesystem --path /tmp/repo`
Includes basic unit & e2e tests. More coverage to be added in a following PR to keep the size contained.
**Updates:**
* Added Repo path sanitization i.e. handle relative paths, make paths cross platform compatible, etc.
* Removed retention artifacts, not supported for filesystem storage.
* cli docs - auto updated.
* Manually tested with all corso backup/restore/export commands.
**Doesn't include**
1. Symlinks
2. User ids wiring into repo.
3. Repos documentation update - in an upcoming PR.
4. Prefix support -> kopia doesn't support prefixes for `filesystem` storage
5. More E2E tests.
---
#### Does this PR need a docs update or release note?
- [ ] ✅ Yes, it's included
- [x] 🕐 Yes, but in a later PR
- [ ] ⛔ No
#### Type of change
<!--- Please check the type of change your PR introduces: --->
- [x] 🌻 Feature
- [ ] 🐛 Bugfix
- [ ] 🗺️ Documentation
- [ ] 🤖 Supportability/Tests
- [ ] 💻 CI/Deployment
- [ ] 🧹 Tech Debt/Cleanup
#### Issue(s)
<!-- Can reference multiple issues. Use one of the following "magic words" - "closes, fixes" to auto-close the Github issue. -->
* #1416
#### Test Plan
<!-- How will this be tested prior to merging.-->
- [x] 💪 Manual
- [x] ⚡ Unit test
- [x] 💚 E2E
