Vulnerability Timeline: When a timeline has a big gap, trim it

[andymeneely]

Motivation Sometimes there's a big gap in time in a timeline, and then all the chiclets get piled up in one tower. We could give ourselves more Check the following:

• [x] I have checked the VHP backlog for something similar: https://github.com/VulnerabilityHistoryProject/vulnerability-history/issues
• [x] I have checked if this should also be part of a Github Project: https://github.com/VulnerabilityHistoryProject/vulnerability-history/projects?type=beta
• [x] I have checked that this might need dev infrastructure or refactor labels