feat: add cpu_usage_millicores and memory_usage_bytes in information_schema.cluster_info table.

[zyy17]

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What's changed and what's your intention?

Wait for GreptimeTeam/greptime-proto#284.

Add cpu_usage_millicores and memory_usage_bytes in information_schema.cluster_info table:

mysql> select peer_hostname, total_cpu_millicores, cpu_usage_millicores, total_memory_bytes, memory_usage_bytes from information_schema.cluster_info;
+-------------------------------------+----------------------+----------------------+--------------------+--------------------+
| peer_hostname                       | total_cpu_millicores | cpu_usage_millicores | total_memory_bytes | memory_usage_bytes |
+-------------------------------------+----------------------+----------------------+--------------------+--------------------+
| mycluster-meta-54bd44bd94-g8dzm     |                 1000 |                    0 |         1073741824 |           28368896 |
| mycluster-meta-54bd44bd94-pkrvx     |                 1000 |                    2 |         1073741824 |           31895552 |
| mycluster-datanode-0                |                 1000 |                    1 |         1073741824 |           34570240 |
| mycluster-datanode-1                |                 1000 |                    1 |         1073741824 |           38170624 |
| mycluster-datanode-2                |                 1000 |                    1 |         1073741824 |           37085184 |
| mycluster-frontend-6c5d4bcf78-m7jtx |                 1000 |                    1 |         1073741824 |           45465600 |
| mycluster-flownode-0                |                 1000 |                    1 |         1073741824 |           43786240 |
+-------------------------------------+----------------------+----------------------+--------------------+--------------------+
7 rows in set (0.00 sec)

With this information, we can easily calculate the total resource usage and may use it to make other decisions about whether to run the high-resource-intensive operation or not.

For now, it only works for a containerized environment.

PR Checklist

Please convert it to a draft if some of the following conditions are not met.

• I have written the necessary rustdoc comments.
• I have added the necessary unit tests and integration tests.
• This PR requires documentation updates.
• API changes are backward compatible.
• Schema or data changes are backward compatible.