As per Gluon recommendation, remove haveged from SITE_PACKAGES:
> Starting with version 19.07 OpenWrt ships the urngd entropy daemon by
> default. It replaces the haveged daemon, for which we removed the
> support in Gluon. Remove haveged from your package selection.

Reference: https://gluon.readthedocs.io/en/latest/releases/v2020.2.html#site-mk

It is now possible to use usb network cards with a x86 offloader like a
futro, removing the need for a pcie network card

Citing the gluon v2018.1 release notes:
    This version changes the flash partition layout on some devices (TP-Link
    CPE/WBS 210/510). To avoid upgrade failures, make sure to upgrade to
    Gluon 2017.1.8 or the latest Gluon 2016.2.x (unreleased) before
    installing Gluon 2018.1.

So we need a yet unreleased ffs-1.4 version and have to bump the version
to 1.5 fot a release with gluon v2018.1.

Setting BUILD_DATE overrides the date used in the generated image names.
With this it is possible to have a consistent build date across all
architectures, making it easier to identify a release. Furthre more it
might be the key to have reproducible builds

gluon-web-mesh-vpn-fastd allows the user to switch between the security and performance VPN settions.

remove ibss

remove ibss mesh