fx: remove delete password function to send more file at once

[bim-g]

fx: remove delete password function to send more file at once

[qgustavor]

Pull request rejected because:

• It changes more that what the pull request describes;
• On previous pull requests and in Rewrite library and release new major version #64 I said I'm against placing examples in readme and in the repository;
• Code style, again, is not being followed;
• I'm against placing dist files in the repository too, those are hosted in NPM;
• Commiting commented code is bad: we use git, if some code needs to be restored just use the history;
• You don't need to store the password to send multiple files at once, just run the upload functions in parallel (although I don't recommend that based on my experience); if you need to reuse the storage instance between processes use JSON serialisation functions (which needs to be documented, see Allow Storage saving and loading #12).