The Dictionary type concern

[yhmtsai]

Currently, NeoFOAM use std::any to store the value of map, which can be anything.
It might be easy to store but will be hard to read.
It is raised in #272
We need to dispatch all type (which can be anything now) to give certain behavior based on the type.
for integer type, it has dispatched int but unsigned int, but users have ability to insert int64, long long, unsigned long long, or etc.
Should we limit the supported type in Dictionary? we do not need to change std::any but maybe use exception or static_assert (if prefer compiling warning) to limit the supported type.