[1.5.1] Upgrade and certify DIL-AI for Integreatly 1.5.1

[honghuac]

Certify and upgrade all content to suit:
https://github.com/integr8ly/installation/releases/tag/release-1.5.1

[honghuac]

Add the installation command that references release tag 1.5.1 of Integreatly, instead of referencing the master branch