Expose Index and Server methods as config actions

Looks super simple in code, I think we should just do this.

I agree with @borisson_, this looks great. Thanks!
Merged. Thanks again!

This is so cool! I believe this is the first contib config action.

1. As a general best practice in recipes, we strive to make recipes/config actions non-destructive. Will removeDatasource, removeProcessor, and removeField present the possibility of a recipe breaking a site? What would those actions be used for?

2. Could we get a change order for this issue? As the first config actions in the contrib space. It would help with documentation in the Recipes Initiative and set precedent for other contrib modules to follow.

Something like this (Note: I am not sure that is how the actions work)

## Search Index

### `setOption/SetOptions` - Set index option(s)

Singular:
```
config:
  action:
    search_api.index.example:
      SetOption:
        cron_limit: 50
```

Plural:
```
config:
  action:
    search_api.index.example:
      SetOptions:
        cron_limit: 50
        index_directly: true
        track_changes_in_references: true
```

### `removeDatasource` - Remove datasource from index

...

### `removeProcessor` - Remove processor from index

...

### `renameField` - Rename index field

...

### `removeField` - Remove field from index

...

## Search Server

### `setBackendConfig` - Set backend config

I think this issue was supposed to be marked as fixed?

1. As a general best practice in recipes, we strive to make recipes/config actions non-destructive. Will removeDatasource, removeProcessor, and removeField present the possibility of a recipe breaking a site? What would those actions be used for?

Yes, those all have the potential to break a site or cause security problems.

2. Could we get a change order for this issue? As the first config actions in the contrib space. It would help with documentation in the Recipes Initiative and set precedent for other contrib modules to follow.

That doesn’t seem like something we normally use change records for, as it’s just a new functionality.
Wouldn’t a documentation page make more sense? I’d support adding a page to our existing documentation, maybe under “Developer documentation”. However, I don’t think I understand recipes and config actions enough to write this myself.