Remove truncation of abstract

[stufraser1]

Abstracts are truncated in layer page and metadata_detail page.

• Remove truncation from abstract limit on metadata_detail page (https://www.geonode-gfdrrlab.org/layers/LAYER/metadata_detail)
• Extend abstract limit on layer page (https://www.geonode-gfdrrlab.org/layers/LAYER). If possible, double, or if this causes other problems, add 50% of current length.
• Propose this change to upstream Geonode development