Vts: refactor encoder code

1. add support use mime to select component instead of component name
2. move GetURL functions to class

Test: atest VtsHalMediaC2V1_0TargetVideoEncTest
Test: atest VtsHalMediaC2V1_0TargetAudioEncTest

Bug: 183454262
Change-Id: I093a1c676c71ba6e771cf53f499376ff61f319b2
2 files changed