Presently, `omdb` can be used to query the database for instance records
using the `omdb instances` command. However, this command does not
output all the database state associated with an instance. Instead, it
displays the instance's name, UUID, effective state, active Propolis
UUID, sled UUID, and sled serial (the last three only if the instance is
running).

This is some of the most useful information about a customer instance,
but it's not *all* of the information we have about it. Debugging issues
related to instance state management may require other information from
the instance record, as well as from the instance's active VMM record,
and its target VMM and active migration records (if it is migrating).
Adding all of these additional details to the `omdb db instances`
command is a bit of a non-starter, though. Since that command outputs a
table of all instances, with one line per instance, the output is
already *much* wider than 80 columns, and requires a pretty wide
terminal to be readable --- once the table has line wrapped, it's much
harder to interpret. Therefore, I've added an `omdb db instance info`
command that outputs a complete dump of the state of a *single*
instance. Since this command is no longer constrained to putting all
salient details about the instance on a single line in a table, we can
show every field in the instance's DB representation without having to
worry about wrapping.

Output from `omdb db instance info` looks like this (yes, I spent
entirely too long tweaking the formatting 😅):

```console
oot@oxz_switch1:~# /var/tmp/omdb-eliza-test-15 db instance show fff916c4-814a-48a0-a04a-f887e6f81a9e
note: database URL not specified.  Will search DNS.
note: (override with --db-url or OMDB_DB_URL)
note: using DNS server for subnet fd00:1122:3344::/48
note: (if this is not right, use --dns-server to specify an alternate DNS server)
note: using database URL postgresql://root@[fd00:1122:3344:109::3]:32221,[fd00:1122:3344:105::3]:32221,[fd00:1122:3344:10b::3]:32221,[fd00:1122:3344:107::3]:32221,[fd00:1122:3344:108::3]:32221/omicron?sslmode=disable
note: database schema version matches expected (98.0.0)

INSTANCE
                     ID: fff916c4-814a-48a0-a04a-f887e6f81a9e
             project ID: fe0da422-5c48-4b52-8010-f2fc401f090f
                   name: app-13
            description: application instance
             created at: 2024-06-22 00:31:43.889412 UTC
       last modified at: 2024-06-22 00:31:43.889412 UTC
/!\          deleted at: 2024-06-22 00:43:59.156149 UTC

CONFIGURATION
                  vCPUs: 1
                 memory: 2 GiB
               hostname: node13
    auto-restart policy: None

RUNTIME STATE
            nexus state: Destroyed
(i)  external API state: Destroyed
        last updated at: 2024-06-22T00:43:49.440274Z (generation 5)
          active VMM ID: None
          target VMM ID: None
           migration ID: None
           updater lock: UNLOCKED at generation: 1
root@oxz_switch1:~# /var/tmp/omdb-eliza-test-15 db instance show 480c6167-dac2-4df7-808d-c9e776c1c312
note: database URL not specified.  Will search DNS.
note: (override with --db-url or OMDB_DB_URL)
note: using DNS server for subnet fd00:1122:3344::/48
note: (if this is not right, use --dns-server to specify an alternate DNS server)
note: using database URL postgresql://root@[fd00:1122:3344:109::3]:32221,[fd00:1122:3344:105::3]:32221,[fd00:1122:3344:10b::3]:32221,[fd00:1122:3344:107::3]:32221,[fd00:1122:3344:108::3]:32221/omicron?sslmode=disable
note: database schema version matches expected (98.0.0)

INSTANCE
                     ID: 480c6167-dac2-4df7-808d-c9e776c1c312
             project ID: fe0da422-5c48-4b52-8010-f2fc401f090f
                   name: mysql-3
            description: MySQL Instance
             created at: 2024-09-16 00:43:10.264333 UTC
       last modified at: 2024-09-16 00:43:10.264333 UTC

CONFIGURATION
                  vCPUs: 4
                 memory: 16 GiB
               hostname: mysql-3
    auto-restart policy: None

RUNTIME STATE
            nexus state: Vmm
(i)  external API state: Stopping
        last updated at: 2024-09-19T23:15:50.698207Z (generation 5)
          active VMM ID: Some(51babee3-0ee5-4f67-bcbb-2189a39479a3)
          target VMM ID: None
           migration ID: None
           updater lock: UNLOCKED at generation: 4

      active VMM record:
          Vmm {
              id: 51babee3-0ee5-4f67-bcbb-2189a39479a3,
              time_created: 2024-09-19T23:15:50.647454Z,
              time_deleted: None,
              instance_id: 480c6167-dac2-4df7-808d-c9e776c1c312,
              sled_id: 71def415-55ad-46b4-ba88-3ca55d7fb287,
              propolis_ip: V6(
                  Ipv6Network {
                      addr: fd00:1122:3344:10b::1:4be,
                      prefix: 128,
                  },
              ),
              propolis_port: SqlU16(
                  12400,
              ),
              runtime: VmmRuntimeState {
                  time_state_updated: 2024-09-19T23:18:03.015643Z,
                  gen: Generation(
                      Generation(
                          4,
                      ),
                  ),
                  state: Stopping,
              },
          }
root@oxz_switch1:~#
```