Implement vim buffer commands :bp, :bn, :bf, :bl and :b[uffer]

[ManuelTS]

Coming from VIM-519 I had my own needs as mentioned in discussions for more buffer commands in this project fitting perfectly CONTRIBUTING.md#a-common-direction
in terms of making ideavim as close as possible to vim

[lippfi]

Hi! First of all, thank you for your time and this PR

• Could you please tell why have you created your own BufferCommand? IdeaVim already has one in the src folder - https://github.com/JetBrains/ideavim/blob/master/src/main/java/com/maddyhome/idea/vim/vimscript/model/commands/BufferCommand.kt . And as I can see in the codebase, commands from src take priorite over commands defined in vim-engine, so your implementation won't be used.
• "first" and "bfirst" commands in Vim do different things. And IdeaVim's implementation of SelectFirstFileCommand and SelectLastFileCommand was incorrect and actually implemented the bfirst and blast commands. But the naming can be confusing now. Could you please rename the files to something like "BfirstCommand" and "BlastCommand" to avoid confusion with "first" and "last"? And also remove mentions of these commands in Java doc like "see :h first"? This commands are also a little bit different to first and last in terms of parsing, e.g. they forbid argument after the command, so could you please review the command flags?

[lippfi]

.

[ManuelTS]

Glad me, thank you for reviewing this PR!

Sorry, I'm far from fluent in kotlin and did some claude code assisted programming, that is the reason. The requested changes should now be done in
af3f14a

[ManuelTS]

But how to implement bp, bn and b[uffer] commands then? As bf and bl are now hopefully done.