Remove the obsolete `remote list` command

Dependencies

• [2] SXEYMYF7 Fixing the bad changes in history (unfortunately, by rebooting).
• [3] 5HF7C67M push/pull: fixed "changes" arguments
• [4] L4JXJHWX pijul/*: reorganize imports and remove extern crate

Change contents

• edit in pijul/src/commands/pushpull.rs at line 26
  [2.112149]→[2.112149:112186](∅→∅)
  − #[clap(name = "list")]

  − List,
• replacement in pijul/src/commands/pushpull.rs at line 34
  [2.112423]→[2.112423:112469](∅→∅)
  − None | Some(SubRemote::List) => {
  [2.112423]

  [2.112469]
  + None => {