Refactor ASF Celix utils to use libuv time/clock api

[pnoltes]

Introduction

The utils api uses struct timespec and clockid_t. This should be replaced with uv_timeval64_t and uv_clock_id.
This will abstract the current Linux-specific implementation and make it cross-platform.

Steps

• Replace ASF Celix public api usage of struct timespec and clockid_t with libuv altenatives.

• Replace ASF Celix internal usage of struct timespec and clockid_t with libuv altenatives.