Prefix common environment variables

[lindluni]

This pull request primarily involves changes to environment variable names and their usage in several groovy scripts under the jenkins/shared-libraries/linux/vars/ directory. The environment variables ORG, REPO, and REF have been renamed to CT_ORG, CT_REPO, and CT_REF, respectively. These changes have been made consistently across all the scripts and their usages.

The changes can be grouped as follows:

Environment variable renaming:

• jenkins/shared-libraries/linux/vars/ExecuteCodeQL.groovy: Renamed ORG to CT_ORG, REPO to CT_REPO, and REF to CT_REF in the call function.
• jenkins/shared-libraries/linux/vars/ExecuteCodeQLWGet.groovy: Renamed ORG to CT_ORG, REPO to CT_REPO, and REF to CT_REF in the call function.
• jenkins/shared-libraries/linux/vars/UploadCodeQLResults.groovy: Renamed ORG to CT_ORG, REPO to CT_REPO, and REF to CT_REF in the call function.

Updates to method calls and URLs:

• jenkins/shared-libraries/linux/vars/ExecuteCodeQL.groovy: Updated the repository and reference parameters in the github upload-results command and the URL for uploading to GitHub in the call function to use the new environment variable names. [1] [2]
• jenkins/shared-libraries/linux/vars/ExecuteCodeQLWGet.groovy: Updated the repository and reference parameters in the github upload-results command and the URL for uploading to GitHub in the call function to use the new environment variable names. [1] [2]
• jenkins/shared-libraries/linux/vars/UploadCodeQLResults.groovy: Updated the repository and reference parameters in the github upload-results command and the URL for uploading to GitHub in the call function to use the new environment variable names. [1] [2]