BaseTools: Use pip module if available, CI uses it by default

Use the new edk2-basetools pip module.
Includes a helpful message in setup to let users know which has been
selected.

Cc: Bob Feng <bob.c.feng@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Yuwei Chen <yuwei.chen@intel.com>

Reviewed-by: Bob Feng <bob.c.feng@intel.com>
Reviewed-by: Yuwei <Chen<yuwei.chen@intel.com>

Signed-off-by: Matthew Carlson <matthewfcarlson@gmail.com>

BaseTools/BinPipWrappers/PosixLike/Ecc

@@ -0,0 +1,13 @@
+#!/usr/bin/env bash
+#python `dirname $0`/RunToolFromSource.py `basename $0` $*
+
+# If a ${PYTHON_COMMAND} command is available, use it in preference to python
+if command -v ${PYTHON_COMMAND} >/dev/null 2>&1; then
+    python_exe=${PYTHON_COMMAND}
+fi
+
+full_cmd=${BASH_SOURCE:-$0} # see http://mywiki.wooledge.org/BashFAQ/028 for a discussion of why $0 is not a good choice here
+cmd=${full_cmd##*/}
+
+export PYTHONPATH="$dir/../../Source/Python${PYTHONPATH:+:"$PYTHONPATH"}"
+exec "${python_exe:-python}" -m $cmd.EccMain "$@"