…#3699)

Issue:
[#3698](#3698)

**Description**
This pull request introduces a feature to the Spring Cloud GCP library,
adding support for the parameter manager module. This enhancement
enables the library to resolve the parameter presented in GCP Parameter
Manager in the `application.properties` file and using the `@Value`
annotation. It also expose the CRUD methods for the Parameter Manager.
It will be implemented the same way as `secretmanager` is implemented.

**Proposed Changes:**
- Add the support of `parametermanager` module in the s`pring-cloud-gcp`
which provides below functionality.
- Inject parameter from Parameter Manager using `@Value` annotation with
specified path i.e `pm@pm@global/my-param/v1`
- Resolve the parameter from the Parameter Manager specified in the
`application.properties` file
- Expose the methods for `createParameter`, `enableParameterVersion`,
`disableParameterVersion`, `deleteParameterVersion`,
`getParameterString`, `deleteParameter`,
`renderedParameterVersionString`
- Add sample application which uses `parametermanager` to showcase the
usecases
- Add the documentation to reflect the new capabilities of
`parametermanager`

Refer to the
[parametermanager.adoc](https://github.com/GoogleCloudPlatform/spring-cloud-gcp/blob/2aecef8378274397ee667dd1a9fbcf72da43355d/docs/src/main/asciidoc/parametermanager.adoc)
file for detailed documentation.

Performed the below mentioned manual unit tests to validate the working
of the global and regional parameter operations.
* Create parameter with given location, parameterId, version and payload
* Create parameter with given project, location, parameterId, version
and payload
* Create parameter with given location, parameterId, version and
payload, format
* Create parameter with given project, location, parameterId, version
and payload, format
* Create parameter with given location, parameterId, version and payload
and invalid projectId (project on which user doesn't have access)
* Enable parameter version with given location, parameterId and version
* Enable parameter version with given project, location, parameterId and
version
* Disable parameter version with given location, parameterId and version
* Disable parameter version with given project, location, parameterId
and version
* Delete parameter with location and parameterId
* Delete parameter with project, location and parameterId
* Delete parameter version with location, parameterId and version
* Delete parameter version with project, location, parameterId and
version
* Check if parameter exist with location and parameterId
* Check if parameter exist with project, location and parameterId
* Check if parameter version exist with location, parameterId and
version
* Check if parameter version exist with project, location, parameterId
and version
* Read parameter with parameter Identifier
* Render parameter with parameter Identifier
* Inject with `@value` annotation
* Read parameter with project, location, parameterId and version for
other project using service account
* Check parameter resolution mentioned in the `application.properties`.

More information about parameter manager:
https://cloud.google.com/secret-manager/parameter-manager/docs/overview

…ry' (#4127)

Issue:
[#4117](#4117)

Changes:

- Make Parameter Manager as `optional dependency` in AutoConfigure
module.
- Changed the `clientFactory` bean name for both Secret Manager and
Parameter Manager.
- Added logic to resolve the registered bean in `spring.factories` only
if the class is present in the classpath for Parameter Manager.
- Added parameter manager module and starter module in
`spring-cloud-gcp-dependencies`.

Testing:
- [x] Created project which uses secretManager
- [x] Created project which uses parameterManager
- [x] Created project which uses secretManager and parameterManager