pkg/sysinfo: move MemInfo and ReadMemInfo to a separate package
Commit 6a516acb2e720b7a01d27c7df9cfe9857c013308 (https://github.com/moby/moby/pull/44663) moved the MemInfo type and ReadMemInfo() function into the pkg/sysinfo package. In an attempt to assist consumers of these to migrate to the new location, an alias was added.

Unfortunately, the side effect of this alias is that pkg/system now depends on pkg/sysinfo, which means that consumers of this (such as docker/cli) now get all (indirect) dependencies of that package as dependency, which includes many dependencies that should only be needed for the daemon / runtime;

- github.com/cilium/ebpf
- github.com/containerd/cgroups
- github.com/coreos/go-systemd/v22
- github.com/godbus/dbus/v5
- github.com/moby/sys/mountinfo
- github.com/opencontainers/runtime-spec

This patch moves the MemInfo related code to its own package. As the previous move
was not yet part of a release, we're not adding new aliases in pkg/sysinfo.

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pkg/system/meminfo_deprecated.go
package system

import "github.com/docker/docker/pkg/sysinfo"

// MemInfo contains memory statistics of the host system.
//
// Deprecated: use [sysinfo.Memory].
type MemInfo = sysinfo.Memory

// ReadMemInfo retrieves memory statistics of the host system and returns a
// MemInfo type.
//
// Deprecated: use [sysinfo.ReadMemInfo].
func ReadMemInfo() (*sysinfo.Memory, error) {
	return sysinfo.ReadMemInfo()
}

package system

import "github.com/docker/docker/pkg/meminfo"

// MemInfo contains memory statistics of the host system.
//
// Deprecated: use [meminfo.Memory].
type MemInfo = meminfo.Memory

// ReadMemInfo retrieves memory statistics of the host system and returns a
// MemInfo type.
//
// Deprecated: use [meminfo.Read].
func ReadMemInfo() (*meminfo.Memory, error) {
	return meminfo.Read()
}

@corhere @cpuguy83 any thoughts? Do you think we should remove it altogether, or "some attempt on creating stub (but compile-time error)?