Morph updates - creation of new forms

Closes #137 

A  first real implementation of new form creation.

The morph plugin holds a `customForm` for every token in its internal state. This customForm can be edited in the `morphFormCreate` directive and pushed to the selectable forms of the morph plugin.

The directive's html is moved out of the main accordion and is now accessed through a button which reveals the `<div>` where the new form is edited.

Pre-fetched forms (as in coming from an external service) can be taken as blueprint to create a new form. The accordion content of such forms has a `Create new` link, which scrolls down to the `morphFormCreate` menu and prefills all values with a copy of the form the user is coming from.

A few raw edges still present. We'd like to enable faster form creation through a nested menu as well - the original plan was to include this inside of this PR already, but this feature is blocked by the refactor of the `nestedMenu` directives currently ongoing in the branch that deals with Smyth's Grammar (PR coming tomorrow or the day after tomorrow).

More work on the morphology plugin will come soon - e.g. updating the context menus so that they can be used effectively.