chore(rtd): Speed up doc build with uv

[effigies]

This PR is aimed at speeding up the build time, which currently clocks in at 2.5m. Let's see if we can't shave off at least 30s.

[effigies]

	Pre-build	Build	Total
Before	88s	60s	148s
After	26s	72s	98s

So we can cut off about a minute (~65%) of pre-build time. Without investigating the range of build times, we're probably going from 2-3 minutes to 1-2 minutes, so a 30-50% saving.

Will leave it to other maintainers to decide if the complexity of the RTD config isn't justified. It's always possible to go back if this is found difficult to maintain, though.

[Remi-Gau]

I would be OK with this

out of curiosity, the virtual is not kept across build is it?

[effigies]

Nope.