feat: More optimal IterateHierarchyV2 and iterateChildrenV2 [#600] (#601)

* chore: More optimal IterateHierarchyV2 and iterateChildrenV2 [#600]

Closes #600

The existing (effectively v1) implementations are suboptimal since they don't construct a graph before the iteration. They search for children by looking at all namespace resources and checking `isParentOf`, which can give `O(tree_size * namespace_resources_count)` time complexity. The v2 algorithms construct the graph and have `O(namespace_resources_count)` time complexity. See more details in the linked issues.

Signed-off-by: Andrii Korotkov <andrii.korotkov@verkada.com>

* improvements to graph building

Signed-off-by: Michael Crenshaw <350466+crenshaw-dev@users.noreply.github.com>

* use old name

Signed-off-by: Michael Crenshaw <350466+crenshaw-dev@users.noreply.github.com>

* chore: More optimal IterateHierarchyV2 and iterateChildrenV2 [#600]

Closes #600

The existing (effectively v1) implementations are suboptimal since they don't construct a graph before the iteration. They search for children by looking at all namespace resources and checking `isParentOf`, which can give `O(tree_size * namespace_resources_count)` time complexity. The v2 algorithms construct the graph and have `O(namespace_resources_count)` time complexity. See more details in the linked issues.

Signed-off-by: Andrii Korotkov <andrii.korotkov@verkada.com>

* finish merge

Signed-off-by: Michael Crenshaw <350466+crenshaw-dev@users.noreply.github.com>

* chore: More optimal IterateHierarchyV2 and iterateChildrenV2 [#600]

Closes #600

The existing (effectively v1) implementations are suboptimal since they don't construct a graph before the iteration. They search for children by looking at all namespace resources and checking `isParentOf`, which can give `O(tree_size * namespace_resources_count)` time complexity. The v2 algorithms construct the graph and have `O(namespace_resources_count)` time complexity. See more details in the linked issues.

Signed-off-by: Andrii Korotkov <andrii.korotkov@verkada.com>

* discard unneeded copies of child resources as we go

Signed-off-by: Michael Crenshaw <350466+crenshaw-dev@users.noreply.github.com>

* remove unnecessary comment

Signed-off-by: Michael Crenshaw <350466+crenshaw-dev@users.noreply.github.com>

* make childrenByUID sparse

Signed-off-by: Michael Crenshaw <350466+crenshaw-dev@users.noreply.github.com>

* eliminate duplicate map

Signed-off-by: Michael Crenshaw <350466+crenshaw-dev@users.noreply.github.com>

* fix comment

Signed-off-by: Michael Crenshaw <350466+crenshaw-dev@users.noreply.github.com>

* add useful comment back

Signed-off-by: Michael Crenshaw <350466+crenshaw-dev@users.noreply.github.com>

* use nsNodes instead of dupe map

Signed-off-by: Michael Crenshaw <350466+crenshaw-dev@users.noreply.github.com>

* remove unused struct

Signed-off-by: Michael Crenshaw <350466+crenshaw-dev@users.noreply.github.com>

* skip invalid APIVersion

Signed-off-by: Michael Crenshaw <350466+crenshaw-dev@users.noreply.github.com>

---------

Signed-off-by: Andrii Korotkov <andrii.korotkov@verkada.com>
Signed-off-by: Michael Crenshaw <350466+crenshaw-dev@users.noreply.github.com>
Co-authored-by: Michael Crenshaw <350466+crenshaw-dev@users.noreply.github.com>