More flexible input parameters for job create

[unkcpz]

The the job script is create with six parameters defined at

hpc-gateway-app/hpc_gateway/model/job.py

Lines 8 to 23 in 060fb85

	def create_job_script(
	job_name, image, email, partition, ntasks_per_node, executable_cmd
	) -> str:
	"""The content of the job script"""
	template = environment.get_template("cscs_job_script.j2")
	content = template.render(
	job_name=job_name,
	email=email,
	ntasks_per_node=ntasks_per_node,
	partition=partition,
	image=image,
	executable_cmd=executable_cmd,
	)
	return content

Not all of them is required and confused for user if they have no much experience with slurm, such as partition. We should make the model of job script creating more flexible so users don't need to specify all those parameters and allowed to set from default.