perf(annotations): increased performance of egef_annotations

The default behaviour of elgg_get_entities_from_annotations was
different from all other elgg_get_entities_from* functions.
This also caused a performance issue on large databases

Fixes #6638
sdfa
applied comments
fix(livesearch): removed custom queries with ege* functions

There was a long standing todo to remove the custom queries in the
livesearch page_handler with elgg_get_entities* functions