Revert external /proc related changes

This reverts these commits:
    a44fb059b1b1e80f5fd5bde3981c4055c648345e
    ec4dbdf1fe6cf65407f17f75c17b0bbd76a31ffa
    b38d999efd6c32797c7cc8eee745bc353dc09edc
    b290171a6533867aae6dc0d3f27dbd58bfb9ff17

Forwarding /proc is a stupid idea. Too much work to do to make it
complete and a lot of corner cases.
Use chmod to hide sensitive info in procfs

Forwarding procfs is not going to work (too complicated). However
we try to hide sensitive information.
Revert "Use chmod to hide sensitive info in procfs"

This reverts commit 5e3216c4cc02844e04df706f1ca40ba24e4929ca.

chmod /proc/A affects /proc/A on the host system, which is terrible.
Revert the commit.