Update GEFS to output numerical icing severity and remove ICIP

[HuiyaChuang-NOAA]

@YaliMao-NOAA will update UPP to output numerical icing severity so that we can compute probabilistic icing severity to meet ICAO 2027 milestone. She already emailed @AndrewBenjamin-NOAA to request a new Grib2 ID for this new variable

Including @bingfu-NOAA and @WenMeng-NOAA for awareness

[AndrewBenjamin-NOAA]

Continuous Icing Severity has been added to Table 4.2-0-19:

240 | Continuous Icing Severity | non-dim | ICESEVCON

[HuiyaChuang-NOAA]

Continuous Icing Severity has been added to Table 4.2-0-19:

240 | Continuous Icing Severity | non-dim | ICESEVCON

Thank you

[HuiyaChuang-NOAA]

@bingfu-NOAA @YaliMao-NOAA
We also may need to add GTG output to a subset or all (if possible) of GEFS members to fulfill ICAO 2027 milestone.
Initially, Yali was going to add generation of GTG in her separated out, stand-alone WAFS package but this option is
no longer valid