RUBY-1021 Use Redacted options class to redact option fields when printing

[estolfo]

No description provided.

[durran]

I envisioned that we would only need to do this in places where the user provides the options, such as:

Mongo::Client#initialize
Mongo::Client#with

And methods like merge need to be implemented in order to not have to wrap every time we call merge in our codebase. Also, methods with signatures such as:

method_name(options = {}) should be changed to method_name(options = Options::Redacted.new)

[estolfo]

ok @durran, I've made all the suggested changes. Let me know if it looks good.

EDIT: I'm actually not convinced this is a good solution. I've realized after testing on jenkins that ssl doesn't work because ssl_options eventually becomes a hash with string keys. I can implement #reject on Options::Redacted to avoid this but it still seems like this is, in general, a fragile solution.
(This line shows why it becomes a hash with string keys: https://github.com/mongodb/mongo-ruby-driver/blob/master/lib/mongo/server/connection.rb#L151 )

[durran]

Don't need the self in front of anything but the self[key] and the direct reference.