feat: add filtering by initiator to provisioner job listing in the CLI (#20137)

Relates to https://github.com/coder/internal/issues/934

This PR provides a mechanism to filter provisioner jobs according to who
initiated the job.
This will be used to find pending prebuild jobs when prebuilds have
overwhelmed the provisioner job queue. They can then be canceled.

If prebuilds are overwhelming provisioners, the following steps will be
taken:

```bash
# pause prebuild reconciliation to limit provisioner queue pollution:
coder prebuilds pause 
# cancel pending provisioner jobs to clear the queue
coder provisioner jobs list --initiator="prebuilds" --status="pending" | jq ... | xargs -n1 -I{} coder provisioner jobs cancel {}
# push a fixed template and wait for the import to complete
coder templates push ... # push a fixed template
# resume prebuild reconciliation
coder prebuilds resume
```

This interface differs somewhat from what was specified in the issue,
but still provides a mechanism that addresses the issue. The original
proposal was made by myself and this simpler implementation makes sense.
I might add a `--search` parameter in a follow-up if there is appetite
for it.

Potential follow ups:
* Support for this usage: `coder provisioner jobs list --search
"initiator:prebuilds status:pending"`
* Adding the same parameters to `coder provisioner jobs cancel` as a
convenience feature so that operators don't have to pipe through `jq`
and `xargs`

cli/testdata/coder_list_--output_json.golden

@@ -45,6 +45,7 @@
         "queue_position": 0,
         "queue_size": 0,
         "organization_id": "===========[first org ID]===========",
+        "initiator_id": "==========[first user ID]===========",
         "input": {
           "workspace_build_id": "========[workspace build ID]========"
         },