Retire the hand-written type layer

[estebanzimanyi]

The binding is a projection of the catalog: MEOS.NET/Types holds the 96
generated object-model classes and nothing else, and the three files the
library still writes by hand are the runtime substrate — the MEOS session
lifecycle, the error check every wrapper makes, and the interpolation enum.
The 70 hand-written type files, the helpers only they used
(DateHelper, EnumConverter, AllocHelper, the TimestampTz struct) and
the folder lists naming their directories are gone with them.

Two members carry a value between the two generated surfaces, which is what
lets the object layer be convenience rather than the only way through:
MEOSObject.Ptr hands a MEOS value to any function on
MEOS.NET.Functions.Meos, and MEOSFactory.Wrap* wraps what such a function
answers back into the class the value's own header names. GoMEOS spells the
same pair Inner() and Init() on each of its hand types.

The ExampleApp reads the whole surface that way: TFloat.In over an instant
answers a TFloatInst, Meos.TfloatOut prints it through its pointer,
Meos.AddTfloatFloat answers a pointer MEOSFactory.WrapTemporal turns back
into a temporal value, a float span set reports its two spans, and a malformed
text raises MEOSInternalErrorException. Sixteen tests read the same surface,
including the interpolation and subtype names MEOS lends out of its static
tables.