Adding Classes for the Portfolio Board endpoints

[AlanHolmes]

Added the classes for the Portfolio Board endpoints: https://developer.teamwork.com/projects/portfolio-boards/boards-in-portfolio-view

There are insert/update/delete/get methods for all classes, even though they are not on the API documentation (I've let teamwork know about this), but they do work.

Portfolio\Board

• getAll /portfolio/boards/ - returns all the portfolio boards
• get /portfolio/boards/{boardId} - returns the specific board
• insert /portfolio/boards - creates a new board
• update /portfolio/boards/{boardId} - updates the given board
• delete /portfolio/boards/{boardId} - deletes the given board

Portfolio\Column

• getAllForBoard /portfolio/boards/{boardId}/columns - returns all the columns for the given board
• get /portfolio/columns/{icolumnId} - returns the specific column
• insert /portfolio/boards/{boardId}/columns - adds a column to the given board
• update /portfolio/columns/{columnId} - updates the given column
• delete /portfolio/columns/{columnId} - deletes the given column

Portfolio\Card

• getAllForColumn /portfolio/columns/{columnId}/cards - returns all the cards for the given column
• get /portfolio/cards/{cardId} - returns the specific card
• insert /portfolio/columns/{columnId}/cards - Adds a project to the given board (thus creating a card)
• update /portfolio/cards/{cardId}/move - Used to move a card from one column to another
• delete /portfolio/cards/{cardId} - deletes the given card (removes the project from the column)

[AlanHolmes]

@simonschaufi made those changes 😄