Add option for when to capture the Elasticsearch query

[felixbarny]

Description

See https://github.com/elastic/apm/issues/665 for background

Spec Issue

• [ ] https://github.com/elastic/apm/issues/673

Agent Issues

• [ ] https://github.com/elastic/apm-agent-java/issues/2745
• [ ] https://github.com/elastic/apm-agent-dotnet/issues/1785
• [ ] https://github.com/elastic/apm-agent-nodejs/issues/2880
• [ ] https://github.com/elastic/apm-agent-python/issues/1612
• [ ] https://github.com/elastic/apm-agent-go/issues/1298
• [ ] https://github.com/elastic/apm-agent-php/issues/745
• [ ] https://github.com/elastic/apm-agent-ruby/issues/1296