cloud-storage

Hi. First of all, kudos to you for the VFS cache - it's really brilliant. I have one request though.

For a little background, as of now I'm using the following settings:

--vfs-cache-mode full \
  --vfs-cache-max-size 500G \
  --vfs-cache-max-age 5000h \
  --vfs-cache-poll-interval 5m \
  --vfs-read-ahead 2G \
  --bwlimit-file 32M \
  --vfs-read-chunk-size=64M \
  --vfs-read-chunk-s

Describe the bug
在当前代码中，HEAD 请求的目标只能是文件，当 HEAD 一个目录时，会返回 404
https://github.com/cloudreve/Cloudreve/blob/4d7b8685b9d0c62d3c115cbe3450f69737f5a506/pkg/webdav/webdav.go#L236-L239

To Reproduce
Steps to reproduce the behavior:
HEAD http://example.com/dav/

Expected behavior
return 0, nil

Additional context
相关方法的 RFC 标准：
http://www.webdav.org/specs/rfc4918.html#rfc.sectio

Please add arm64 release bin

When a new account is added under a provider, two similar nodes appear in navigation view. This happens for the first time only. On subsequent loads, this issue is not observed.