Enhancement: Add single files to configurations for workspaces

[callahanp]

Add single files to workspace as patterns in a workspace folder.

microsoft/vscode#45177

Configuration item: "workspaceFiles": ["the-path/the-file-name",...]

Generate a workspace folder for each separate path in the set and include each file on that path, as shown below.
{
"folders":
[
{
"path": "the-path",
"file_include_patterns": ["the-file-name",...],
"folder_exclude_patterns": ["**"]
}
]
}