add FIDES_DEPRECATED macro

Just grabbed VTK-m deprecation macros to be used here.

docs/dev/changelog/deprecation.md

+# Add FIDES_DEPRECATED macro
+
+The `FIDES_DEPRECATED` macro allows us to remove (and usually replace)
+features from Fides in minor releases while still following the conventions
+of semantic versioning. The idea is that when we want to remove or replace
+a feature, we first mark the old feature as deprecated. The old feature
+will continue to work, but compilers that support it will start to issue a
+warning that the use is deprecated and should stop being used. The
+deprecated features should remain viable until at least the next major
+version. At the next major version, deprecated features from the previous
+version may be removed.
+The deprecation code was adapted from VTK-m, so if you're familiar with
+deprecation in VTK-m, it works the same for Fides.
+
+## Declaring things deprecated
+
+Classes and methods are marked deprecated using the `FIDES_DEPRECATED`
+macro. The first argument of `FIDES_DEPRECATED` should be set to the first
+version in which the feature is deprecated. For example, if the last
+released version of Fides was 1.0, and on the master branch a developer
+wants to deprecate a class foo, then the `FIDES_DEPRECATED` release version
+should be given as 1.1, which will be the next minor release of Fides. The
+second argument of `FIDES_DEPRECATED`, which is optional but highly
+encouraged, is a short message that should clue developers on how to update
+their code to the new changes. For example, it could point to the
+replacement class or method for the changed feature.
+
+`FIDES_DEPRECATED` can be used to deprecate a class by adding it between the
+`struct` or `class` keyword and the class name.
+
+``` cpp
+struct FIDES_DEPRECATED(1.1, "OldClass replaced with NewClass.") OldClass
+{
+};
+```
+
+Aliases can similarly be depreciated, except the `FIDES_DEPRECATED` macro
+goes after the name in this case.
+
+``` cpp
+using OldAlias FIDES_DEPRECATED(1.1, "Use NewClass instead.") = NewClass;
+```
+
+Functions and methods are marked as deprecated by adding `FIDES_DEPRECATED`
+as a modifier before the return value.
+
+``` cpp
+FIDES_DEPRECATED(1.1, "You must now specify a tolerance.") void ImportantMethod(double x)
+{
+  this->ImportantMethod(x, 1e-6);
+}
+```
+
+`enum`s can be deprecated like classes using similar syntax.
+
+``` cpp
+enum struct FIDES_DEPRECATED(1.2, "Use NewEnum instead.") OldEnum
+{
+  OLD_VALUE
+};
+```
+
+Individual items in an `enum` can also be marked as deprecated and
+intermixed with regular items.
+
+``` cpp
+enum struct NewEnum
+{
+  OLD_VALUE1 FIDES_DEPRECATED(1.2, "Use NEW_VALUE instead."),
+  NEW_VALUE,
+  OLD_VALUE2 FIDES_DEPRECATED(1.2) = 42
+};
+```
+
+## Using deprecated items
+
+Using deprecated items should work, but the compiler will give a warning.
+That is the point. However, sometimes you need to legitimately use a
+deprecated item without a warning. This is usually because you are
+implementing another deprecated item or because you have a test for a
+deprecated item (that can be easily removed with the deprecated bit). To
+support this a pair of macros, `FIDES_DEPRECATED_SUPPRESS_BEGIN` and
+`FIDES_DEPRECATED_SUPPRESS_END` are provided. Code that legitimately uses
+deprecated items should be wrapped in these macros.
+
+``` cpp
+FIDES_DEPRECATED(1.1, "You must now specify both a value and tolerance.")
+void ImportantMethod()
+{
+  // It can be the case that to implement a deprecated method you need to
+  // use other deprecated features. To do that, just temporarily suppress
+  // those warnings.
+  FIDES_DEPRECATED_SUPPRESS_BEGIN
+  this->ImportantMethod(0.0);
+  FIDES_DEPRECATED_SUPPRESS_END
+}
+```