Add skipLevels and skipScreenSpaceErrorFactor

Description

When loadAncestors is enabled, the renderer continuously loads parent ancestor tiles as backups so that there is content to display while high-precision child tiles are being loaded. The current logic adds all ancestor tiles containing content to the download queue, which can result in a large number of unnecessary downloads when there are many intermediate layers. However, if loadAncestors is disabled, there can be a long visual gap before the high-precision child tiles finish loading, during which no suitable fallback content is available to display.
Therefore, a compromise is needed: allowing the renderer to skip certain intermediate levels while still loading some ancestor fallback tiles. This can provide a smoother visual transition while reducing loading time and memory usage.

Solution

Cesium's skipLevels and skipScreenSpaceErrorFactor can solve this problem, maybe we can also add these options in the traverseFunction

Alternatives

Currently, if current level is 1 and target level is 6, with loadAncestors = true, the current loading logic is 1->2->3->4->5->6, with loadAncestors = false, it would be 1->6

If set skipLevels = 1, the loading logic will be 1->3->5->6

Additional context

No response

Start at the renderer's traverseFunction and review how ancestor tiles are added to the download queue. Compare the requested skipLevels and skipScreenSpaceErrorFactor behavior with the linked Cesium 3D Tileset options. Done means intermediate levels can be skipped while selected ancestor fallback tiles still load, including the 1→6 example described in the issue.