refactor!: unify the API of getting total cpu and memory

[zyy17]

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What's changed and what's your intention?

1. Add get_total_cpu_millicores() / get_total_cpu_cores() / get_total_memory_bytes() / get_total_memory_readable() in common-stat to unify the API of getting total CPU and memory.

   • The original implementation by using num_cpus::get() can not handle the non-integer cgroups cpu limit(for example, 1500m);

2. Breaking changes in information_schema.cluster_info table:

   • cpus -> total_cpu_millicores(use the millicores as the basic unit)
   • memory_bytes -> total_memory_bytes

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.

[sunng87]

@zyy17 I already have typo fixes in #7047
We can merge that standalone pr first.