API struggles with getting all 700 sites

[peterdudfield]

Detailed Description

Currently we can get 100/200 sites but above this, the API struggles. It looks like the database works for all sites, but then something doesnt work in the API.

Context

• For showing on Passiv sites on a map, its useful to pull all sites.
• A customer might have more sites, and we might have to think of a different way to do this

Possible Implementation

• Would be good to bench mark how long it takes now
• The UI just to pull 100 sites in batches.
• Look which part of the API is being slow

[peterdudfield]

We can try it out again after #102

[peterdudfield]

This should help with #102