treewide: purge gluon-mesh-babel (#3105)

.github/labeler.yml

docs/user/site.rst

package/features

package/gluon-l3roamd/Makefile

package/gluon-mesh-babel/Makefile

package/gluon-mesh-babel/check_site.lua

...otplug.d/iface/90-gluon-babel-brclient-configure-snooping

package/gluon-mesh-babel/files/etc/init.d/gluon-mesh-babel

package/gluon-mesh-babel/files/lib/gluon/respondd/client.dev

...n-mesh-babel/files/lib/gluon/state/check.d/has_neighbours

...el/luasrc/lib/gluon/upgrade/300-gluon-mesh-babel-mkconfig

...el/luasrc/lib/gluon/upgrade/310-gluon-mesh-babel-firewall

package/gluon-mesh-babel/src/Makefile

package/gluon-mesh-babel/src/handle_neighbour.c

package/gluon-mesh-babel/src/handle_neighbour.h

package/gluon-mesh-babel/src/neighbours-babel.c

package/gluon-mesh-babel/src/respondd.c

...us-page/files/lib/gluon/status-page/view/status-page.html