Add ratings section to reader overlay

[fancydancers]

Adds a section to reader overlay to set ratings. Includes buttons to clear and set rating, both will rebuild tags div after setting.

• add $ to the end of url returned by LRR.getTagSearchURL to return exact tag. This was particularly noticeable for ratings as rating:⭐⭐⭐ would also return for 4 and 5 stars but could also result in unwanted results for normal tags.
• move tag object to list functionality found in index.js into function as the same pattern is used for updating reader tags