Use system credential instead of global one

[tim-goto]

Describe the bug

the plugin currently only accepts global credentials that are available to all jenkins users/jobs/.. This poses a security risk as this credential can be read by any user. Instead the plugin should be able to accept a system credential which can only be accessed by jenkins administrators

Current behavior

see above

Reproduction steps

No response

Expected behavior

No response

JFrog plugin version

1.5.0

JFrog CLI version

2.56.1

Operating system type and version

linux

JFrog Artifactory version

No response

JFrog Xray version

No response