ipsec-tools: remove

ipsec-tools: remove

As discussed on GitHub[0] the package should be removed.

[0]: https://github.com/openwrt/packages/issues/7832

> The package is effectively orphaned upstream and has been for some
  time. Given the security-sensitive nature of the package, an active
  maintainer community is essential for safe usage. Racoon's lack of
  support for IKEv2, despite it being stable for a long time, and the
  availability of next-generation tunneling systems such as wireguard,
  also would seem to limit its future value. Setkey's functionality
  has been subsumed by 'ip xfrm'.

> If you disagree that ipsec-tools should be removed from OpenWRT,
  please say so now. If there are still use cases for it that are
  not met by other IKE implmenentations that would be good to
  know. But more importantly, I think you'll need to convince us
  that ipsec-tools is actually safe to operate on today's Internet
  given its current state of development.

Signed-off-by: Paul Spooren <mail@aparcar.org>