test-schedule-tmt*: add TMT_PLUGIN_REPORT_REPORTPORTAL_LINK_TEMPLATE

Part of TFT-2757.

Related MRs: gluetool-modules!910 (merged), oculus!80 (merged), !899 (merged)

This MR enables a new tmt reportportal plugin option (--link-template) introduced in tmt 1.46 (release notes).