White-space at the end of enabled paths is not trimmed

Problem/Motivation

When pasting in a list of pages to enable Optimize on from an external source, such as excel, it's possible for a user to accidentally paste in white-space characters at the end of a path. This can lead to confusion as to why the scripting is not loaded.

Steps to reproduce

1. Enter a path with white-space at the end
2. Visit the page without white-space
3. Observe that the scripting is not loaded

Proposed resolution

Trim each line prior to saving the configuration. If any space characters are required, they can be encoded.

Remaining tasks

1. Trim the input on save
2. Provide a notice explaining that white-space is trimmed
3. Tests

User interface changes

None

API changes

None

Data model changes

None - subsequent saves to the form may remove trailing white-space from each line.