Feature request: exclude pagination parameters from export_url

[mattbuff]

Can pagination parameters be excluded from export_url? My rationale is that the presence of pagination parameters does not affect the resulting export, but it does cause cache misses. Excluding them could significantly improve caching performance for expensive exports.

For example, the following URLs produce the same download, but are considered different items by URL-based server-side caching systems.

/?page=2&_export=csv
/?page=5&_export=csv

[jieter]

Seems very reasonable, PRs welcome!