Insert many performance optimizations

[Valerionn]

Some insertMany micro optimizations, leading to ~50% more Operations/s in my local insert-many benchmarks (but feel free to run the benchmarks on your PC as well):

Changes, sorted by performance impact (DESC):

• Only create events array if there are actually event listeners for the onInsert event.
• No longer use primaryKey.has to throw PrimaryKeyAlreadyInUseError, instead just try setting the btree value, using overwrite = false. If the key already exists, this function returns false and the error can be thrown there. This takes away one tree traversal for has, leading to better performance (unless the user sets clone = true and regularly inserts entries which throw a PrimaryKeyAlreadyInUseError, because the element is now cloned first, and then the insert afterwards checks if the element exists. But I think it's reasonable to optimize the non-error-case, especially since Error throwing is usually slow anyways).
• Entity-independent calls to table[BlinkKey].storage.primary etc. are now only done once in the beginning instead of once for each entity. This should slightly increase performance as well.

Possible further improvements, which are breaking changes:

• Change onInsert event from { entity: T }[] to T[] so that it's not necessary to allocate new objects for the events list
• Don't return primary keys (or provide an optimized insertMany function which doesn't return them)

[codecov[bot]]

Codecov Report

:exclamation: No coverage uploaded for pull request base (feature/fix-insert-many-performance@18b3f6b). Click here to learn what that means. The diff coverage is n/a.

@@                          Coverage Diff                           @@
##             feature/fix-insert-many-performance      #22   +/-   ##
======================================================================
  Coverage                                       ?   95.12%           
======================================================================
  Files                                          ?       74           
  Lines                                          ?     1128           
  Branches                                       ?      261           
======================================================================
  Hits                                           ?     1073           
  Misses                                         ?       55           
  Partials                                       ?        0           

:mega: We’re building smart automated test selection to slash your CI/CD build times. Learn more