Default all subcommands to use Debug mode #1151

As a part of the progress of making moon behavior uniform and predictable, we will correct the behavior of all moon subcommands to:

• Build mode: Default to debug for everything. The only exception is when the subcommand requires optimization to take place, and using debug just doesn't make sence (currently only bench and bundle) -- in this case it will default to release.
• Debuginfo: Default on across every command, unless the user explicitly uses --strip to turn it off. In other words, --no-strip will be deprecated.