ffmuc-mesh-vpn-wireguard: only use gluon.mesh_vpn

[grische]

@maurerle as discussed:
Instead of having a custom wireguard.mesh_vpn.enabled toggle always enable wireguard mesh vpn when gluon.mesh_vpn.enabled is enabled.

[maurerle]

This PR is not needed.
the wireguard mesh_vpn enabled setting is set in the gluon provider directly:

community-packages/ffmuc-mesh-vpn-wireguard-vxlan/luasrc/usr/lib/lua/gluon/mesh-vpn/provider/wireguard.lua

Lines 19 to 22 in 33bfda1

	function M.enable(val)
	uci:set('wireguard', 'mesh_vpn', 'enabled', val)
	uci:save('wireguard')
	end

Just like it is done for the upstream package:

https://github.com/freifunk-gluon/gluon/blob/d4847b697c1fb9da44751d659072e77e4dae6967/package/gluon-mesh-vpn-wireguard/luasrc/usr/lib/lua/gluon/mesh-vpn/provider/wireguard.lua#L19

So no change of this is required