Rewrite end of month / same day conventions

[asladeofgreen]

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[Avi-D-coder]

Extracted from my actus-rs comments:

In the Java a EOMC only applies to periods of months, not days, weeks, or years.
The data dictionary docs above implies that EOMC applies quarters as well.
Quarters, and Half years are not distinct concepts in the Java.

EOM

If EndOfMonth is specified, but the anchor date is not the last day of the month,
then the Java silently ignores the EOMC, and uses the SameDay convention.
I think applying it to all periods is more reasonable.

SD

SameDay does not check that cyclic dates fall on the same day of the month.
In the Java SameDay::shift = id.

This means that you cannot specify a recurrence on the 30th if your cycle anchor is in February.

Solution

EOMC::NoShift should be added.
SameDay should be replaced with a semantically sound definition.

A ShiftTowards(DayOFMonth) convention could replace both EOM and SameDay.
ShiftTowards is more general, it's semantically sound, it can shift towards any day of the month, and plays better with non whole month cycle periods.

Under the new conventions ShiftTowards(31) = EOM, ShiftTowards(30) is a well defined version of SameDay sans the CycleAnchor != 30 case which would be represented as NoShift.