Partial replacement of ISO 19108 by `java.time` API

[desruisseaux]

The following interfaces were derived from ISO 19108:2002 (Temporal Schema), but only empty place-holders were released in GeoAPI 3.0. Since that time, the Java standard library got a new java.time package. Given that ISO 19108 has not been used a lot in GeoAPI and that the java.time package is quite advanced, the Java profile of GeoAPI should use the standard Java library instead of ISO 19108 when a correspondence exists. The following mapping can apply:

ISO identifier	GeoAPI interface (Java)	Java standard API
TM_Duration	org.opengis.temporal.Duration	java.time.temporal.TemporalAmount
TM_IntervalLength	org.opengis.temporal.IntervalLength	java.time.Duration
TM_PeriodDuration	org.opengis.temporal.PeriodDuration	java.time.Period

The following sub-sections compare the ISO and Java specifications:

TM_Duration → TemporalAmount

• ISO TM_Duration: A data type to be used for describing length or distance in the temporal dimension. Note: in practice, this is an empty interface defined only as the base interface of TM_IntervalLength and TM_PeriodDuration.
• Java TemporalAmount: Framework-level interface defining an amount of time, such as "6 hours", "8 days" or "2 years and 3 months". This is the base interface type for amounts of time. Note: this is the base interface of Duration and Period.

TM_IntervalLength → Duration

• ISO TM_IntervalLength: A data type for intervals of time which supports the expression of duration in terms of a specified multiple of a single unit of time.
• Java Duration: A time-based amount of time, such as '34.5 seconds'. This class models a quantity or amount of time in terms of seconds and nanoseconds.

TM_PeriodDuration → Period

• ISO TM_PeriodDuration: Uses the format specified by ISO 8601 for exchanging information about the duration of a period.
• Java Period: A date-based amount of time in the ISO-8601 calendar system, such as '2 years, 3 months and 4 days'. This class models a quantity or amount of time in terms of years, months and days.

[desruisseaux]

This task is related to #79.

[desruisseaux]

The mapping has been documented in the package Javadoc and in Metanorma.