add support for .connectignore

[edavidaja]

• specifying files to ignore via the --exclude option makes for very long command line arguments
• the exclude patterns do not work consistently, see exclude glob patterns do not work on Windows #320
• our current globbing implementation is a bit limited
• the meaning of extra_files is not easy to reason about across app modes, see deploying "EXTRA_FILES" needs to be explained better #354

❯ rsconnect deploy voila
Usage: rsconnect deploy voila [OPTIONS] PATH [EXTRA_FILES]...

❯ rsconnect deploy notebook
Usage: rsconnect deploy notebook [OPTIONS] FILE [EXTRA_FILES]...

❯ rsconnect deploy streamlit
Usage: rsconnect deploy streamlit [OPTIONS] DIRECTORY [EXTRA_FILES]...

Introducing a .connectignore would make it simpler to document which files should be ignored by a deployment.
pathspec looks like an appealing candidate for enhanced wildcard support.

[aronatkins]

The rsconnect R package has rudimentary support for an .rscignore file. Should the two packages support the same file name and format?

[edavidaja]

Ideally (to me):

• they should both support a .connectignore
• .connectignore should follow the same rules as .gitignore

[r-leyshon]

+1 for this feature. I have a bunch of local tables with differing vintages. I only want to include the latest marked with a datetime filename. Being able to take max() from a globstring would be perfect,