Autoclonetype2 (bp #1804) (#1810)

* [plugin] Split ChiselComponent into its own file

(cherry picked from commit e80e9a3b)

* [plugin] Implement autoclonetype in the compiler plugin

(cherry picked from commit 14942312)

* [plugin] Stop autoclonetype stack traces when using plugin

The compiler plugin obviates the need for using stack traces to
determine outer objects in autoclonetype. When the plugin was used to
compile a given Bundle, it will no longer collect a stack trace upon
construction. This should have massive benefits to elaboration runtime.

(cherry picked from commit a8d32388)

* [plugin] Disable BundleComponent by default, add option to enable

(cherry picked from commit 3bea6167

)

* Fix plugin scalacOptions for 2.11

* allowReflectiveAutoCloneType must work outside of Builder context

Co-authored-by: Jack Koenig <koenig@sifive.com>