Mount overlaybd devices in journal mode

This is slower but safer. All writes will go through the journal.

Use a proper image name for the imported tar image

When an image is imported from tar without an annotation for the image
name, we generate a fake one. Make sure it is valid.

Create and use a lease in the Compare method to prevent GC (#24)

containerd is not forwarding the lease used by nerdctl. We must set our
own, time-expiring lease until it is fixed upstream.

Otherwise our objects get garbage collected before we can make
references to them.

Add a diff service to Overlaybd snapshotter (#21)

This diff service identifies whether the Compare function is operating
on overlaybd devices, and if so, attempts to call overlaybd-commit on
the writable_data and writable_index of the upper layer, efficiently
generating a blob for the writable layer.

This is much faster than the default diff service, which mounts the
block devices and compares the filesystem's file-by-file, which
generates an OCI tar which we then convert to overlaybd.

Remove extra logs (#20)

**What this PR does / why we need it**:

**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(,
fixes #<issue_number>, ...)` format, will close the issue(s) when PR
gets merged)*:
Fixes #

**Please check the following list**:
- [ ] Does the affected code have corresponding tests, e.g. unit test,
E2E test?
- [ ]  Does this change require a documentation update?
- [ ] Does this introduce breaking changes that would require an
announcement or bumping the major version?
- [ ]  Do all new files have an appropriate license header?

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convertor: Retry on 5xx errors (#19)

**What this PR does / why we need it**: Also retry on 5xx errors.
Occasionally we get various gateway errors or just 500 errors, the retry
logic should apply to these too.

**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(,
fixes #<issue_number>, ...)` format, will close the issue(s) when PR
gets merged)*:
Fixes #

**Please check the following list**:
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- [ ]  Does this change require a documentation update?
- [ ] Does this introduce breaking changes that would require an
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- [ ]  Do all new files have an appropriate license header?

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Check the parent snapshot to identify the writable type (#17)

**What this PR does / why we need it**:

**What**
Changes getWritableType() to look at the *parent* snapshot's filesystem
instead of the child's, which doesn't even exist at this point.

**Why**
When creating sandboxes/containers from overlaybd pause images, the
first creation works correctly but subsequent attempts fall back to
overlayfs mode instead of using overlaybd.

The getWritableType() function was checking the child snapshot's labels
and filesystem for overlaybd metadata, but the child snapshot doesn't
have a label, and the child snapshot directories don't exist yet at this
point.


**Please check the following list**:
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E2E test?
- [ ]  Does this change require a documentation update?
- [ ] Does this introduce breaking changes that would require an
announcement or bumping the major version?
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Cleanup tracing and propagate traceparent (#16)

Traceparent and baggage get propagated to overlaybd-tcmu via the image
config file.

Bump golang version in ci action (#15)

**What this PR does / why we need it**: Bumps ci.yml golang version to
match go.mod. Without this the ci action is failing with `go: go.mod
requires go >= 1.23.0 (running go 1.22.0; GOTOOLCHAIN=local)`

**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(,
fixes #<issue_number>, ...)` format, will close the issue(s) when PR
gets merged)*:
Fixes #

**Please check the following list**:
- [ ] Does the affected code have corresponding tests, e.g. unit test,
E2E test?
- [ ]  Does this change require a documentation update?
- [ ] Does this introduce breaking changes that would require an
announcement or bumping the major version?
- [ ]  Do all new files have an appropriate license header?

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Merge pull request #13 from runloopai/adam/no-timeout

Use the same HTTP timeout settings as skopeo