Allow setting field trials

[rnett]

Is your feature request related to a problem? Please describe.

CreatePeerConnectionFactory takes a FieldTrialsView that can be used to enable experimental features (like message interleaving) - the underlying data type is a string -> string map. Currently, no ability to set this is exposed to the Java API.

Describe the solution you'd like

A way to create connection factories with custom field trials is available.

[devopvoid]

Hi @rnett, I will add this to the next release!

[rnett]

Awesome, thanks!