Implement repeat and repeat_interleave for data duplication

## 🚀 Feature

Implement `repeat` and `repeat_interleave` functions to duplicate all data structures like Meshes, Textures, etc.

## Motivation

Currently, the function to duplicate data is `extend` which seems (a bit surprisingly) to follow the `repeat_interleave`'s pytorch convention. However in many other use cases, one would like to duplicate data using the other `repeat` convention

## Pitch

Concretely, this amounts to renaming `extend` as `repeat_interleave` and create a new duplication function called `repeat` for all data structures

No files, tests, or entry points are named. Start by locating the existing extend implementations for Meshes, Textures, and other data structures, then define how repeat and repeat_interleave should differ and verify that both conventions work consistently across all of them.

Written by the indexing model from the issue text.