Gpuciscripts clean and update

[msadang]

In CI folder the following changes have been made:

• Remove logger function and replace all logger calls with gpuci_logger

• Removed all ellipses ... from logger messages

• Prepend /opt to the conda path in PATH variable

• Replace conda with gpuci_conda_retry for build and install calls (Did not replace conda activate with gpuci_conda_retry)

• Replace source activate with the following:
  . /opt/conda/etc/profile.d/conda.sh
  conda activate rapids

• Replace conda list with more verbose information:
  conda info
  conda config --show-sources
  conda list --show-channel-urls

• Update Copyright year in the top of scripts to include 2020 if applicable

• Set PARALLEL_LEVEL to ${PARALLEL_LEVEL:-4}

• Set gpuci_conda_retry flags in cpu/build.sh
  Setup 'gpuci_conda_retry' for build retries (results in 2 total attempts)
  export GPUCI_CONDA_RETRY_MAX=1
  export GPUCI_CONDA_RETRY_SLEEP=30

• Replace calls to gcc and g++ with $CC and $CXX respectively

[GPUtester]

Please update the changelog in order to start CI tests.

View the gpuCI docs here.

[msadang]

gpuci_logger and parallel level changed.