Consider using service proxies for info modules

[Simon Hensel]

Currently, the Openstack.Cloud collection uses the connection.search_* functions to retreive data in the *_info modules.

These functions are not only currently bugged and don't apply filters correctly (see https://bugs.launchpad.net/openstacksdk/+bug/2051698), but are also marked as deprecated:
https://github.com/openstack/openstacksdk/blob/f9ce151f903f5cba2ce13f9531640fec3b0e5bfd/openstack/cloud/_network.py#L51

For example, when retrieving projects, replace conn.search_projects() with conn.identity.projects(**query):
https://github.com/openstack/ansible-collections-openstack/blob/e009f80ffce5975d69018b8badd46297c7a90ec6/plugins/modules/project_info.py#L122

These service proxies are already used when changing or creating projects (or any type of resource for that matter):
https://github.com/openstack/ansible-collections-openstack/blob/e009f80ffce5975d69018b8badd46297c7a90ec6/plugins/modules/project.py#L214

These search_* cloud layer functions use the proxy layer under the hood anyways, so why not make all API calls uniform and avoid deprecated functions?
The contributor guide also lists proxy methods as preferred over the cloud layer.
The cloud collection version 2.X also requires the latest version of the openstacksdk (>=1.0), so it makes sense IMO to update to the more modern proxy interface.

This is to incite some discussion, I am happy to provide patches should this change be desired.