cmd/httpdfs: implement [libhttp.Server] with [memfs.MemFS]

The httpdfs accept single directory to be served under HTTP server,
with the following options,

  -address <IP:PORT>
	Run the HTTP server on specific IP address and port.
    	Default to ` + defAddress + `.

  -exclude <regex>
	Exclude the files matched by regex from being served.
	Default to empty, none of files is excluded.

  -help
	Print this usage.

  -include <regex>
	Serve only list of files matched with regex.
	Default to include CSS, HTML, JavaScript, ICO, JPG, PNG, and
	SVG files only.

  -version
	Print the program version.

0 files changed, 0 insertions, 0 deletions