Add option to package configuration by type into the profile

Problem/Motivation

Currently the 'profile' assignment plugin pulls and adapts code from the Standard install profile but doesn't allow assigning configuration by type.

Proposed resolution

• Add a configuration form, with checkboxes for selecting configuration types, parallel to the 'core' and other assignment methods' configuration forms.
• Add a small set of configuration types by default, mutually exclusive of those set by default in other assignment plugins.
• On the form, also add options for the existing functionality (copying files and dependencies from the Standard install profile).
• Give the 'profile' assignment plugin a higher default weight so it runs after 'core' and 'site'.

Remaining tasks

User interface changes

Adds a configuration link and form for the 'profile' assignment plugin.