Have an import testing method that does not error out

[justinGilmer]

Sometimes we might need to check if an importable module exists, and import if it does and if it does not, move on gracefully. Currently we have the import_ method, which tests an import and then returns an error if the module is not found.

Maybe we want to have a non-error generating import_ method. Most of the times these should error out, but in certain cases it might be useful?

Curious what others think?

Originally posted by @justinGilmer in #604

[mikemhenry]

maybe import_(module_name, quite=True) so depending the situation we can set quiet=False

[mattwthompson]

So we want a "try to import, but don't error out if the import fails" flag, which is off by default (by default we would want an error)