Rotate every 100MB over enb.xlog, enb.xlog.1, ... enb.xlog.9

Add a service that runs `xamari xlog stats[samples,rf]/<period>s` in
enb/gnb instance. For now the resulting logfile enb.xlog/gnb.xlog is
placed in monitor public folder to be served by monitor http server.

Optionally the service also includes `x.drb_stats/<period>s`, which
implies 100Hz polling. This is enabled by default.

* Rename mme software type to core-network since mme is a 4G terminology
* Rename template-lte-XXX to template-XXX since lte is a 4G terminology

* Remove gnb-epc and enb-epc software types and merge mme and epc together

The recipe slapos.cookbook:requestoptional may cannot finish the request
correctly during slapos node instance. With slapos.cookbook:request,
the waitForInstance can retry multiple times until the request finished.

* Add check-rx-saturated promise
* Add IMSI in SIM connection parameters

Credit: This originally based on XU Lu's work
I rewrite it base on Romain's comment and add the tests