feat(sdk): Enable containerizing v2 Python components (#6417)

* Refactor and move all v2 related code to under the v2 namespace.

Most of the changes are around imports and restructuring of the
codebase. While it looks like a lot of code was added, most of the code
already existed and was simply moved or copied over to v2. The only
exceptions are:
- under kfp/v2/components/component_factory.py: some helper functions
  were copied with simplification from _python_op.py
- we no longer strip the `_path` suffix in v2 components.

Note: there is still some duplication of code (particularly between
component_factory.py and _python_op.py), but it's ok for now since we
intend to replace some of this with v2 ComponentSpec + BaseComponent.

* Update setup.py.

* update tests.

* revert accidental change of gcpc

* Fix component entrypoint.

* Update goldens.

* fix tests.

* fix merge conflict.

* revert gcpc change.

* fix tests.

* fix tests.

* Add type aliases for moved files.

* merge and update goldens.

* Add a CLI command to help containerize and build v2 components.

* Flesh out the CLI for Docker.

* update comments.

* Support multiple component files in the same directory.

* address pr comments.

* Let user specify just the directory containing components.

The CLI will search for components in all Python files by default. It
can also search for a specific filepattern (as supported by
pathlib.Path objects).

Also add a bunch of tests.

* Clean up.

* fix merge error.

* Fix docker import error for tests.

* Update release notes.

* address PR comments.

sdk/RELEASE.md

@@ -3,6 +3,9 @@
 ## Major Features and Improvements
 
 * Add v2 placeholder variables [\#6693](https://github.com/kubeflow/pipelines/pull/6693)
+* Add a new command in KFP's CLI, `components`, that enables users to manage and build
+  v2 components in a container with Docker [\#6417](https://github.com/kubeflow/pipelines/pull/6417)
+
 
 ## Breaking Changes
 
@@ -22,6 +25,7 @@
 * Depends on `typing-extensions>=3.7.4,<4; python_version<"3.9"` [\#6683](https://github.com/kubeflow/pipelines/pull/6683)
 * Depends on `click>=7.1.2,<9` [\#6691](https://github.com/kubeflow/pipelines/pull/6691)
 * Depends on `cloudpickle>=2.0.0,<3` [\#6703](https://github.com/kubeflow/pipelines/pull/6703)
+* Depends on `typer>=0.3.2,<1.0` [\#6417](https://github.com/kubeflow/pipelines/pull/6417)
 
 ## Documentation Updates
 

sdk/python/kfp/cli/cli.py

@@ -12,15 +12,19 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import click
 import logging
 import sys
+
+import click
+import typer
+
 from kfp._client import Client
 from kfp.cli.run import run
 from kfp.cli.pipeline import pipeline
 from kfp.cli.diagnose_me_cli import diagnose_me
 from kfp.cli.experiment import experiment
 from kfp.cli.output import OutputFormat
+from kfp.cli import components
 
 
 @click.group()
@@ -67,6 +71,7 @@ def main():
     cli.add_command(pipeline)
     cli.add_command(diagnose_me, 'diagnose_me')
     cli.add_command(experiment)
+    cli.add_command(typer.main.get_command(components.app))
     try:
         cli(obj={}, auto_envvar_prefix='KFP')
     except Exception as e: