Create trt plugin base (#69487)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/69487
Write customized plugin for trt requires extend IPluginV2IOExt. This diff extract functions that should share comon impl between plugins from IPluginV2IOExt into plugin_base, make writing customized plugin for oss user easier.
This diff also fix double creator issue, the root cause is about get_trt_plugin in converters.py look for plugin by name matching. Swith to use the util function from converters_utils.py resolve the issue.
Test Plan: CI
Reviewed By: 842974287
Differential Revision: D32747052
fbshipit-source-id: 7f2e8811c158230f66a0c389af4b84deaf7e2d1f
