New plugins

[freedev]

Hi, I wrote few plugins for recent and legacy Solr versions:

• Solr Custom Payload Score QParser Plugin
• Solr Payload String Custom Function Query
• Solr constant-similarity aka Solr e-commerce similarity aka Solr Fixed Similarity
• Solr Payload Legacy Custom Function Query backport of payloads function queries to Solr 5.x

Maybe some of these can be useful to the community.

[tboeghk]

Thanks, I'll add them over the next days!