Backfill API documentation for Private Domains and Resource Match endpoints

[#73431654]

Signed-off-by: Dave Liebreich <dliebreich@pivotallabs.com>
Backfill API documentation for Routes endpoint

[#73431654]

Signed-off-by: Dave Liebreich <dliebreich@pivotallabs.com>
Backfill API documentation for Spaces endpoint

- Extend standard_model_list to support nested endpoints

[#73431654]

Signed-off-by: Dave Liebreich <dliebreich@pivotallabs.com>