Remove OPERATIONAL mode

Since questions come up all the time what OPERATIONAL mode exactly does, it is recommended to make all the OPERATIONAL settings config keys for improved transparency.

"OPERATIONAL" function	"RESEARCH" mode	Mitigation strategy
Avoid "fake" first time step	Fake first time step to define all output	Invoke SNOWPACK with command line option -r (restart mode). This is a crucially important command line option for stop-and-go simulations!!!
When slope angle > 0: PERP_TO_SLOPE = TRUE	Both PERP_TO_SLOPE TRUE / FALSE possible	Set PERP_TO_SLOPE = TRUE for slope stations
VW_DRIFT *= wind_scaling_factor	wind_scaling_factor from *sno file ignored. WIND_SCALING_FACTOR can still be provided in [SnowpackAdvanced]	WIND_SCALING_FACTOR must be specified in [SnowpackAdvanced]. The wind scaling factors in *sno files will be ignored.
AVGSUM_TIME_SERIES in [OUTPUT] set to FALSE	AVGSUM_TIME_SERIES can be set to TRUE or FALSE	Set AVGSUM_TIME_SERIES to FALSE in [OUTPUT]
Throw when CANOPY = TRUE	CANOPY can be TRUE or FALSE	Make sure to set CANOPY = FALSE in [SNOWPACK]
Skipping the check for proper PSUM resampling definition	Check for PSUM resampling definition	Run the check for all cases
INFLATE_ALLOW must be set to TRUE or FALSE	INFLATE_ALLOW can be set to TRUE or FALSE, default: FALSE	Set INFLATE_ALLOW to TRUE or FALSE
DETECT_GRASS forced to TRUE Removed in commit f89d8c17	DETECT_GRASS can be TRUE or FALSE (default: FALSE)	Setting DETECT_GRASS = TRUE in ini file (optional, preferably only for IMIS stations with a grass-growth problem)
Skipping deleting old output files	Deleting old output (*.sno, *.ini) files	This is probably not an issue, otherwise, introduce a boolean [Output] key
Skipping writing configuration to output *ini	All configuration keys written to output *ini files	TODO
Hard-coded accumulation of flat field runoff in operational mode	Unclear if exactly the same can be achieved in research mode	TODO
loc_for_snow and loc_for_wind in Hazard data set in a specific way	loc_for_snow and loc_for_wind in Hazard data set in an other specific way	TODO
progress message suppressed	progress message shown	TODO
Meteo.cc: force MO_MICHLMAYR for operational mode when temperatures are high enough	Atmospheric stability correction as applied as specified with key ATMOSPHERIC_STABILITY	Operational SNOWPACK would benefit anyway from a non-neutral atmospheric stability correction
Hazard.cc: different calculation for dewpt_def	different calculation for dewpt_def	Not clear where this variable is used. Seems to be only inserted in ImisDB, so seems irrelevant now?
Snowpack.cc: No treatment of no-snow effect on albedo	Special treatment of "No Snow" on the ground	Research mode approach seems okay for operational applications as well, I think.

To be amended.