feat: add L_default_args

[jmattaa]

Added global constant L_default_args to lua:

L_default_args = {
    all = false, -- show hidden files
    files = true, -- show files
    directories = true, -- show directories
    symlinks = true, -- show symlinks
    git = false, -- show git status and entries tracked by git
    long = false, -- show long format

    filters = {}, -- apply filters defined in `L_filters`
                    -- (NOTE: the name should be a string)
}