Feature/add folders to test collection

[lance-sp]

this PR gets rid of the path in vscode coming from the pytestPath property in the config file.
it will use the lowest directory it finds, instead.
it was an initial attempt to maintain the folder structure for the .mustrd.ttl in the vsccode test explorer

however,
it seems that to get proper nesting, we'll need to rethink the current approach which nests the .mustrd.ttl under the mustrd-config.ttl file
in essence, the pytest expects to find a .py file, in some directory, and then specs within that, and then test functions under that.
i think to achieve this, we'll need to change the collect_file to find .mustrd.ttl files that match the current config, but this is a bigger change than i'm prepared to try, right now.

so what we get, is in deeply nested files, the directory immediately above becomes the name of the node, but they're all flattened immediately underneath the mustrd_config.ttl

[lance-sp]

i have published this as alpha to 0.6.0a1

to install use pip install mustrd==0.6.0a1 --pre