refactor: mark public names as public

[mortenpi]

JuliaHub.jl follows the convention that all private names start with _, so we can do the loop automatically. There is still an list in the tests that we cross-check. Also, since we support all the way back to 1.6 right now, we need to make is conditional on Base.ispublic being there (and this would stay true even if bump that to the 1.10 LTS).

Will fix these warnings:

[pfitzseb]

Can't say I love the idea of programmatically marking all functions as public that follow a given naming scheme instead of explicitly marking them as public, but I guess it's fine 😅

[mortenpi]

I don't disagree actually. In principle, this list could be turned into public statements instead

JuliaHub.jl/test/runtests.jl

Lines 178 to 200 in c9a711d

	Symbol("@script_str"),
	:AbstractJobConfig, :AbstractJuliaHubApp,
	:appbundle, :AppBundleSizeError, :ApplicationJob, :Authentication,
	:AuthenticationError, :BatchJob, :BatchImage, :ComputeConfig,
	:Dataset, :DatasetReference, :DatasetVersion,
	:DefaultApp, :FileHash, :InvalidAuthentication, :InvalidRequestError, :Job,
	:WorkloadConfig, :JobFile, :JobLogMessage, :JobReference, :JobStatus,
	:JuliaHubConnectionError, :JuliaHubError,
	:JuliaHubException,
	:Limit, :NodeSpec, :PackageApp, :PackageJob, :Unlimited,
	:PermissionError, :script, :Secret, :UserApp,
	:application, :applications, :authenticate,
	:batchimage, :batchimages,
	:check_authentication, :current_authentication,
	:dataset, :datasets, :delete_dataset, :download_dataset, :download_job_file,
	:extend_job,
	:interrupt!, :isdone, :job, :job_file, :job_files,
	:job_logs, :job_logs_buffered, :job_logs_newer!, :job_logs_older!,
	:AbstractJobLogsBuffer, :KafkaLogsBuffer,
	:hasfirst, :haslast, :jobs, :kill_job,
	:nodespec, :nodespecs, :reauthenticate!, :submit_job,
	:update_dataset, :upload_dataset, :wait_job,
	:request,

and then we could check the naming convention in the tests. But it gets a bit annoying if we also have to support <= 1.10, since there's no way to list / filter for public names there.