".." in directory does not work (at least not on Windows)

[fireattack]

Test with config.json:

{
    "extractor": {
        "postprocessors": [
            {
                "name": "metadata",
                "event": "after",
                "directory": [".."],
                "filename": "!metadata.jsonl",
                "mode": "jsonl",
                "open": "a"
            }
        ]
    }
}

Prior to 1bdb0f7, use .. will unexpectedly change the dir to root drive. After that fix, it straightly up throws errors on Windows:

>python -m gallery_dl -c config.json --config-ignore "https://en.wikipedia.org/wiki/File:Malabar_pied_hornbill_(Anthracoceros_coronatus)_male.jpg"
.\gallery-dl\wikipedia\File_Malabar_pied_hornbill_(Anthracoceros_coronatus)_male.jpg\Malabar pied hornbill (Anthracoceros coronatus) male (4a77f077).jpg
[wikimedia][error] Unable to download data:  OSError: [Errno 22] Invalid argument: '\\\\?\\C:\\files\\repo\\gallery-dl_og\\gallery-dl\\wikipedia\\File_Malabar_pied_hornbill_(Anthracoceros_coronatus)_male.jpg\\..\\!metadata.jsonl'

Related: #5262 (comment)

[fireattack]

It looks like path.py has all the batteries to solve this (mainly, os.path.abspath() which would resolve relative path(s)):

gallery-dl/gallery_dl/path.py

Lines 196 to 202 in 5f6a891

	if WINDOWS and self.extended:
	# Enable longer-than-260-character paths
	directory = os.path.abspath(directory)
	if directory.startswith("\\\\"):
	directory = "\\\\?\\UNC\\" + directory[2:]
	else:
	directory = "\\\\?\\" + directory

but it isn't used in _directory_format. I see lots of other places are still manually joining paths, too. Maybe we can create a static method for that?

gallery-dl/gallery_dl/postprocessor/metadata.py

Lines 156 to 167 in 5f6a891

	def _directory_format(self, pathfmt):
	formatters = pathfmt.directory_formatters
	conditions = pathfmt.directory_conditions
	try:
	pathfmt.directory_formatters = self._directory_formatters
	pathfmt.directory_conditions = ()
	segments = pathfmt.build_directory(pathfmt.kwdict)
	directory = pathfmt.clean_path(os.sep.join(segments) + os.sep)
	return os.path.join(pathfmt.realdirectory, directory)
	finally:
	pathfmt.directory_conditions = conditions
	pathfmt.directory_formatters = formatters