feat(rum-explorer): allow setting exact start and end dates

[aem-code-sync[bot]]

Hello, I'm the AEM Code Sync Bot and I will run some actions to deploy your branch and validate page speed. In case there are problems, just click a checkbox below to rerun the respective action.

• [ ] Re-run PSI checks
• [ ] Re-sync branch

Commits

* [81964ec](https://github.com/adobe/helix-website/commit/81964ec2a8ad288cfa7b9e95fa27a6332ae4624b) :white_check_mark: (latest) * [8f30bda](https://github.com/adobe/helix-website/commit/8f30bda034b3cb0bac783e58a3d7b844e0aad80f) :white_check_mark: