RANGER-5126: Add workflow to test Ranger Upgrades in Docker

[kumaab]

What changes were proposed in this pull request?

Adding an on-demand workflow to run and test ranger upgrades from released versions to the upcoming release.

• download earlier releases instead of building them
• run upgrades across multiple db flavors: mysql, oracle and postgres
• refactor changes to include build-branch as input (upcoming release), for ex: ranger-2.7

(cherry picked from commit f33a8764d4488aaf4db404d827cbe8eb9e329709)

How was this patch tested?

Triggered GitHub Actions using the below command:

╰─ gh workflow run upgrade-ranger.yaml --field build-branch="ranger-2.7" -R https://github.com/kumaab/ranger
✓ Created workflow_dispatch event for upgrade-ranger.yaml at master

CI run: https://github.com/kumaab/ranger/actions/runs/16309860266