bug#44297: [Feature request] project.el: Additional utility functions

[Juri Linkov <juri@linkov.net>]

> It would be nice if project.el had the following interactive functions:
>
> project-find-other-file: Find a file with the same basename as the current file but a different extension 

Maybe then it should be named project-find-other-extension?
Otherwise, project-find-other-file might imply a similarity
with find-alternate-file (C-x C-v).

Another question: how it should work?  Maybe running this command
should completing-read on all files with the same basename
ignoring the extension?

> project-find-file-in-directory: completing-read for a directory within
> the project, and then within the selected directory, completing-read
> for a file within that directory
> project-find-directory: completing-read for a directory within the project

Another useful command would be:
project-find-file-only using completing-read to match on file names only,
not on directory parts.

> project-recentf: completing-read recently-accessed files in the project

All project file-reading commands could provide a list of recent files
as the default values available via M-n key presses.

> project-gdb: GDB in project root directory