Renamed shadow type constants, old constants are deprecated

[mvaligursky]

Not marking this as breaking, as old constants are still working fine, just marked as deprecated.

renames done:

SHADOW_PCF1_FLOAT16 -> SHADOW_PCF1_16F
SHADOW_PCF3_FLOAT16 -> SHADOW_PCF3_16F
SHADOW_PCF5_FLOAT16 -> SHADOW_PCF5_16F
SHADOW_PCSS -> SHADOW_PCSS_32F
SHADOW_PCF1 -> SHADOW_PCF1_32F
SHADOW_PCF3 -> SHADOW_PCF3_32F
SHADOW_PCF5 -> SHADOW_PCF5_32F
SHADOW_VSM16 -> SHADOW_VSM_16F
SHADOW_VSM32 -> SHADOW_VSM_32F

SHADOW_VSM8 is unmodified and will be completely removed in following PR.