Webscrapbook

* Fixed bad CSS rewriting for a bad URL token or a URL with escaped newlines or certain escaped control chars when converting an item to single_file format.

* Fixed bad CSS rewriting when converting an item to single_file format.

* Improved MIME types handling:
* Fixed bad MIME to file extention conversion in some platforms.
* The user config is now allowed to overwrite the patch rules of WebScrapBook.
* Reworked internal constants `WSB_USER_DIR` and `WSB_USER_CONFIG` to be the subpath under the user home directory and can be overwritten by the environment variables.
* Miscellaneous code optimization.

* Added a restriction for download workers, which can be tweaked through option `capture.downloadWorkers`.

* Fixed bad handling of ID-datetime conversion for some rare cases.
* Added support for salted hash when caching authorization information for better security.

* Added support of opening an archive file using the `wsb` executable.
* When viewing archive files, no more deduplicate the provided paths and use the original case for them.
* Deprecated the `webscrapbook` and `wsbview` executables: use `wsb` instead.
* Fixed bad encoding for the indexer and some CLI utilities in some cases.
* Fixed timestamp handling issues, which may crash the server, for the default theme.