System / Web - Add schema search functionality

[dvstans]

Add ability to search for schemas using:

• ID text fragment (ngram index)
• Text (description fulltext index)
• Owner
• Topic (once schemas are associated with topics)
• Sort order (ID+ver, owner, text relevance, topic match relevance)

[dvstans]

This is done for now. Topics will be added via a new ticket when appropriate.