Updating metadata service model definitions to use camelCase

[deasydoesit]

With underscored model attributes, usage of camelCase queries was prevented leading to errors like column key_to_assets.entityKey does not exist when using the following access pattern:

KeyToAsset.findOne({
  where: {
    entityKey: bs58.decode(eccCompact),
  },
  include: [IotHotspotInfo, MobileHotspotInfo],
});

Per the following excerpt from Sequelize docs, since we're using the underscored option during model init, we don't need to provide snake case model attributes.

With the underscored option enabled, Sequelize will instead define:

- A createdAt attribute for each model, pointing to a column named created_at in each table
- An updatedAt attribute for each model, pointing to a column named updated_at in each table
- A userId attribute in the Task model, pointing to a column named user_id in the task table

https://sequelize.org/docs/v6/other-topics/naming-strategies/#the-underscored-option