BHoM_Adapter: update&correct Toolkit template

Once the refactoring (#84) is done, update the Visual Studio Template for the generation of the Toolkits code.

This should also include a correction of the previous behaviour that moved some files in the wrong folder, as illustrated in the wiki itself.

- [ ] **1) Update to latest refactored adapter structure**
- [ ] **2) Correct/expand/improve the comments**
- [ ] **3) Update/improve the [Engine Method Templates](https://github.com/BuroHappoldEngineering/BHoM_Documentation/issues/32#issuecomment-501270421)**

### 2) Correct/expand/improve the comments
Tips I would've found useful:
* Above the adapter constructor, specify that any parameter added will be reflected automatically in the parameters of the GH/Dyn/Excel component.

Corrections I would find useful:
* Having distinct comment "regions" for `Private methods` and `Private fields` is not correct by definition (fields include the methods). Rename `Private fields` to `Private variables`.
* The comment region `Public Fields` seems to appear twice.
* I would delete the `Public Fields` naming and replace it with two: `Public Properties` and `Public Methods (Push, Pull, and any other public method)`.

## Additional notes
Closes https://github.com/BuroHappoldEngineering/BHoM_Documentation/issues/32