Switch built-in policies to .actions.rollover.max_primary_shard_size

[rodrigc]

In the Kibana UI, when looking at ILM policies related to apm-server, I see warnings:

Maximum index size is deprecated and will be removed in a future version. Use maximum primary shard size instead.

To avoid confusion for the end-user, I recommend that the same changes which were done in elasticsearch's default ILM policies be done for apm-server:

Related to:

• Enhance rollover API and ILM rollover action to specify max single primary shard size elasticsearch#63026
• Switch built-in policies to max_primary_shard_size elasticsearch#69995 by @joegallo
• Use max_primary_shard_size instead of max_size beats#25000