Make `methods.get_cpus_and_memory` more general

[zhuchcn]

The definition of the methods.get_cpus_and_memory function is too specific and should be converted to more general.

metapipeline-DNA/config/methods.config

Lines 71 to 86 in b8a6347

	detect_cpus_and_memory = {
	if (params.partition ==~ /F\d*/) {
	def cpus = params.partition.replaceAll('F', '') as Integer
	// F-series 1:2 CPU:memory ratio
	def memory = 2 * cpus * 0.95 // 5% of memory is unavailable based on Slurm configuration
	return ['cpus': cpus, 'memory': memory]
	} else if (params.partition ==~ /M\d*/) {
	def cpus = params.partition.replaceAll('M', '') as Integer
	// M-series 1:16 CPU:memory ratio
	def memory = 16 * cpus * 0.95 // %5 of memory is unavailable based on Slurm configuration
	return ['cpus': cpus, 'memory': memory]
	} else {
	System.out.println("Failed to detect CPUs and memory for ${params.partition}. Using default values.")
	return [:]
	}
	}

Options:

1. Always require users to specify the number of cpus and memory per sample
2. Use SLURM commands to get the number of cpus and memory per partition.