Added __main__ script, added dpctl/resources/cmake to gitignore

Indended usage of the main module is

```bash
python -m dpctl --includes   # prints include flags for dpctl headers
```

```bash
python -m dpctl --cmakdir   # prints directory to be used as DPCTL_ROOT \
                            # for cmake to find dpctl package
```

```bash
python -m dpctl --library   # prints linker flags for linking \
                            # to SyclInterface library
```

Author: oleksandr-pavlyk

.gitignore

@@ -99,3 +99,6 @@ dpctl/_sycl_queue.h
 dpctl/_sycl_queue_manager.h
 dpctl/memory/_memory.h
 dpctl/tensor/_usmarray.h
+
+# moved cmake scripts
+dpctl/resources/cmake

dpctl/__main__.py

@@ -0,0 +1,83 @@
+#                      Data Parallel Control (dpctl)
+#
+# Copyright 2020-2021 Intel Corporation
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import argparse
+import os
+import os.path
+import platform
+import sys
+
+import dpctl
+
+
+def _dpctl_dir() -> str:
+    abs_path = os.path.abspath(dpctl.__file__)
+    dpctl_dir = os.path.dirname(abs_path)
+    return dpctl_dir
+
+
+def print_includes() -> None:
+    "Prints include flags for dpctl and SyclInterface library"
+    print("-I " + dpctl.get_include())
+
+
+def print_cmake_dir() -> None:
+    "Prints directory with FindDpctl.cmake"
+    dpctl_dir = _dpctl_dir()
+    print(os.path.join(dpctl_dir, "resources", "cmake"))
+
+
+def print_library() -> None:
+    "Prints linker flags for SyclInterface library"
+    dpctl_dir = _dpctl_dir()
+    plt = platform.platform()
+    ld_flags = "-L " + dpctl_dir
+    if plt != "Windows":
+        ld_flags = ld_flags + " -Wl,-rpath," + dpctl_dir
+    print(ld_flags + " -lSyclInterface")
+
+
+def main() -> None:
+    """Main entry-point."""
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        "--includes",
+        action="store_true",
+        help="Include flags dpctl headers.",
+    )
+    parser.add_argument(
+        "--cmakedir",
+        action="store_true",
+        help="CMake module directory, ideal for setting -DDPCTL_ROOT in CMake.",
+    )
+    parser.add_argument(
+        "--library",
+        action="store_true",
+        help="Linker flags for SyclInterface library.",
+    )
+    args = parser.parse_args()
+    if not sys.argv[1:]:
+        parser.print_help()
+    if args.includes:
+        print_includes()
+    if args.cmakedir:
+        print_cmake_dir()
+    if args.library:
+        print_library()
+
+
+if __name__ == "__main__":
+    main()