* lisp/arc-mode.el (archive--file-desc): Add fields from other structs

* lisp/arc-mode.el (archive--file-desc): Add fields from other structs

Add fields `size`, `time` (used by all backends) as well as
`pos`, `ratio`, `uid`, and `gid` (used only be some backends).

(archive-arc--file-desc, archive-rar--file-desc, archive-ar--file-desc)
(archive-lzh--file-desc, archive-zip--file-desc, archive-7z--file-desc):
Remove defstructs.
(archive-arc-summarize): Record size and time in the descrs.
(archive-lzh-summarize): Record size, time, uid, and gid in the descrs.
(archive-zip-summarize): Record size and time in the descrs.
(archive-zoo-summarize): Record size and time in the descrs.
(archive-rar-summarize): Adjust to use of `archive--file-desc`.
(archive-7z-summarize): Adjust to new constructor.
(archive-ar-summarize): Adjust to use of `archive--file-desc`.

(archive-ar-write-file-member): Remove mode-to-int hack.
(archive-get-descr): Directory entries aren't regular members.