[PHP] Provide an up-to-date best practice config in the docs

[dkarlovi]

Problem Statement

Currently, there's a bunch of features in this SDK which needs to be enabled. They're currently "pending" or need manual work, it would make sense to explain to the user what exactly to do and how.

Examples which could be documented:

1. Monolog handler instead of built in one, which seems like the desired direction for the future
2. filtering out HTTP 4xx and similar exceptions, the old Ignore Integration doesn't seem to work when you're using Monolog
3. adding environment and version, environment differs from the Symfony environment (for example, both staging and prod deployment would run in prod Symfony environment)
4. breadcrumbs vs Monolog fingers crossed handler

There's probably others, but having recommended solutions to these would already be a great start.

Solution Brainstorm

Provide a best practice config snippet (or a few for most common scenarios) which would represent the best intersection of what the community comes up with as solutions.

[getsantry]

Assigning to @getsentry/support for routing ⏲️

[getsantry]

Routing to @getsentry/product-owners-sdks-web-backend for triage ⏲️

[dkarlovi]

This is actually related specifically to Symfony SDK, it it makes a difference.