Plugin should advertise version and features in HTCondor machine ads

[matyasselmeci]

Pelican Service:

• [ ] Client
• [X] Plugin
• [ ] Registry
• [ ] Director
• [ ] Origin
• [ ] Cache
• [ ] Other (please give the detail)

HTCondor 23.7.1 is expected to add a feature that will let file transfer plugins advertise arbitrary classad attributes, as described in this ticket: HTCONDOR-1051. OSPool currently advertises the plugin version by hand (in the OSDF_PLUGIN_VERSION and STASH_PLUGIN_VERSION attributes), but it would be nice if the plugin itself did that for us.

In addition, the plugin could advertise the availability of certain features. For example, the ?recursive=true feature was added in 7.7.0, so a user wanting to use that feature needs to land on a machine with plugin version >= 7.7.0. It would be nicer if the user didn't have to remember the specific version and could just put the feature in their requirements.

Strawman example: add this to the output of condor_stash_plugin -classad:

StartdAttrs = "OsdfPluginVersion, OsdfPluginFeatures"
OsdfPluginVersion = "7.8.0"
OsdfPluginFeatures = "pack, recursive"

[matyasselmeci]

I tagged this for 7.9.0 since HTCondor 23.7.1 is going to be released in early May, which would not let you test it in time for 7.8.0.