Add provisionSystem API with proxy option

[aaannz]

What does this PR change?

Using web ui it is possible to schedule system provisioning through specific proxy. This is not possible using any API call. This commit adds this missing provisionSystem API call and related unit tests.
Automatic proxy detection based on request headers is preserved.

GUI diff

No difference.

• DONE

Documentation

• API documentation added: please review the Wiki page Writing Documentation for the API if you have any changes to API documentation.

• DONE

Test coverage

ℹ️ If a major new functionality is added, it is strongly recommended that tests for the new functionality are added to the Cucumber test suite

• Unit tests were added

• DONE

Links

Issue(s): https://github.com/SUSE/spacewalk/issues/25636
Port(s): # add downstream PR(s), if any

• DONE

Changelogs

Make sure the changelogs entries you are adding are compliant with https://github.com/uyuni-project/uyuni/wiki/Contributing#changelogs and https://github.com/uyuni-project/uyuni/wiki/Contributing#uyuni-projectuyuni-repository

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Re-run a test

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• Re-run test "changelog_test"
• Re-run test "backend_unittests_pgsql"
• Re-run test "java_pgsql_tests"
• Re-run test "schema_migration_test_pgsql"
• Re-run test "susemanager_unittests"
• Re-run test "javascript_lint"
• Re-run test "spacecmd_unittests"

Before you merge

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[github-actions]

👋 Hello! Thanks for contributing to our project.
Acceptance tests will take some time (aprox. 1h), please be patient ☕
You can see the progress at the end of this page and at https://github.com/uyuni-project/uyuni/pull/9464/checks
Once tests finish, if they fail, you can check 👀 the cucumber report. See the link at the output of the action.
You can also check the artifacts section, which contains the logs at https://github.com/uyuni-project/uyuni/pull/9464/checks.

If you are unsure the failing tests are related to your code, you can check the "reference jobs". These are jobs that run on a scheduled time with code from master. If they fail for the same reason as your build, it means the tests or the infrastructure are broken. If they do not fail, but yours do, it means it is related to your code.

Reference tests:

• https://github.com/uyuni-project/uyuni/actions/workflows/acceptance_tests_secondary_parallel.yml?query=event%3Aschedule

• https://github.com/uyuni-project/uyuni/actions/workflows/acceptance_tests_secondary.yml?query=event%3Aschedule

KNOWN ISSUES

Sometimes the build can fail when pulling new jar files from download.opensuse.org . This is a known limitation. Given this happens rarely, when it does, all you need to do is rerun the test. Sorry for the inconvenience.

For more tips on troubleshooting, see the troubleshooting guide.

Happy hacking!
⚠️ You should not merge if acceptance tests fail to pass. ⚠️

[github-actions]

Suggested tests to cover this Pull Request

• sle_ssh_minion
• min_salt_migration
• min_salt_install_with_staging
• proxy_register_as_minion_with_script
• min_deblike_salt
• allcli_overview_systems_details
• min_salt_formulas
• min_project_lotus
• srv_docker_cve_audit
• minssh_move_from_and_to_proxy
• min_salt_install_package
• srv_monitoring
• min_salt_openscap_audit
• minkvm_guests
• min_monitoring
• min_recurring_action
• min_salt_minion_details
• min_rhlike_openscap_audit
• srv_distro_cobbler
• min_salt_minions_page
• min_deblike_salt_install_package
• min_empty_system_profiles
• min_cve_id_new_syntax
• min_ssh_tunnel
• allcli_sanity
• min_move_from_and_to_proxy
• min_ansible_control_node
• srv_power_management_redfish
• min_bootstrap_script
• min_rhlike_monitoring
• allcli_software_channels_dependencies
• min_cve_audit
• min_salt_mgrcompat_state
• min_config_state_channel
• srv_reportdb
• buildhost_bootstrap
• minssh_salt_install_package
• allcli_reboot
• minssh_bootstrap_api
• proxy_retail_pxeboot_and_mass_import
• min_rhlike_salt_install_package_and_patch
• min_deblike_monitoring
• min_deblike_salt_install_with_staging
• min_check_patches_install
• srv_scc_user_credentials
• srv_cobbler_distro
• min_rhlike_salt
• min_salt_lock_packages
• srv_rename_hostname
• proxy_branch_network
• min_bootstrap_api
• minssh_ansible_control_node
• srv_first_settings
• allcli_action_chain
• min_salt_formulas_advanced
• srv_cobbler_profile
• srv_power_management
• min_salt_user_states
• allcli_config_channel
• min_virthost
• min_deblike_openscap_audit
• min_action_chain
• min_config_state_channel_subscriptions
• min_timezone
• buildhost_osimage_build_image
• srv_advanced_search
• min_activationkey
• allcli_software_channels
• min_bootstrap_reactivation
• srv_maintenance_windows
• min_salt_pkgset_beacon
• proxy_as_pod_basic_tests
• buildhost_docker_build_image
• sle_minion
• min_deblike_ssh
• min_salt_software_states
• min_rhlike_ssh
• minssh_action_chain
• min_custom_pkg_download_endpoint
• allcli_system_group
• proxy_cobbler_pxeboot
• min_bootstrap_ssh_key
• min_retracted_patches
• min_change_software_channel
• proxy_container
• proxy_container_branch_network
• srv_user_configuration_salt_states
• minssh_tunnel
• proxy_container_cobbler_pxeboot
• srv_push_package
• srv_task_status_engine
• srv_errata_api
• proxy_container_retail_pxeboot
• proxy_container_retail_mass_import