[Visualizations] Remove the setters/getters from the plugin

[stratoula]

Describe the feature:
Right now on the Visualizations plugin https://github.com/elastic/kibana/blob/master/src/plugins/visualizations/public/plugin.ts#L32, we use setters to set the services that the plugin needs and getters to get the services and use them wherever we want.

We want to remove this logic as it makes the code more complex and may cause some bugs.

So, for example, many setters are used to the wizard modal. We could change it to something like:
createShowNewVisModal(deps) => showNewVisModal

and ideally, remove the services.ts file.

[elasticmachine]

Pinging @elastic/kibana-app (Team:KibanaApp)

[stratoula]

Duplicate of #63596