Normalize embedders names

[sgrava]

Currently, we have:

• BaseEmbedder
• EmbeddingConfig
• GraphToGraphEmbedder
• MatrixToGraphEmbedder
• InteractionEmbeddingConfig
• InteractionEmbedder
• SpringLayoutConfig
• SpringLayoutEmbedder

To normalize the namespace, we could always replace Embedding with Embedder, so to have

• BaseEmbedder
• EmbedderConfig
• GraphToGraphEmbedder
• MatrixToGraphEmbedder
• InteractionEmbedderConfig
• InteractionEmbedder
• SpringLayoutEmbedderConfig
• SpringLayoutEmbedder

Actions

• Decide if it is worth to normalize the names

[sgrava]

@v-vitale let's decide here which name scheme to use.
It will be breaking for users to change names, but we can always output a good deprecation message for the old ones.

[v-vitale]

I would chose one between Embedding and Embedder. I would opt for Embedder.