Add documentation for boundary classes

...ava/de/unikoblenz/fgbks/base/utils/UniqueIdGenerator.java

...nikoblenz/fgbks/base/utils/boundary/AbstractBoundary.java

...nz/fgbks/base/utils/boundary/AbstractGrowingBoundary.java

...va/de/unikoblenz/fgbks/base/utils/boundary/BoundType.java

...ava/de/unikoblenz/fgbks/base/utils/boundary/Boundary.java

...tils/boundary/BoundaryOperationNotSupportedException.java

...enz/fgbks/base/utils/boundary/BoundaryParseException.java

...blenz/fgbks/base/utils/boundary/impl/BooleanBoundary.java

...ikoblenz/fgbks/base/utils/boundary/impl/DateBoundary.java

...oblenz/fgbks/base/utils/boundary/impl/DoubleBoundary.java

...blenz/fgbks/base/utils/boundary/impl/IntegerBoundary.java

...blenz/fgbks/base/utils/boundary/impl/InvalidBoundary.java

...ikoblenz/fgbks/base/utils/boundary/impl/LongBoundary.java

...oblenz/fgbks/base/utils/boundary/impl/StringBoundary.java