This release adds logs correlation and telemetry support:
- Used configurations, libraries and integrations will be collected. This may be disabled with `DD_INSTRUMENTATION_TELEMETRY_ENABLED=0`.
- Logs written by common logging libraries will be attached metadata about the trace and span the log line was generated in. This may be disabled with `DD_LOGS_INJECTION=0`.

### Added
- Add Logs Correlation #2118
- Add network destination name to http client spans #2134
- Add peer.service to Mysqli instrumentation #2142
- Add peer.service to PHPRedis instrumentation #2152
- Add peer.service to PDO instrumentation #2148
- Add peer.service to SQLSRV instrumentation #2155
- Add peer.service to Mongodb instrumentation #2147
- Add peer.service to Memcached clients instrumentation #2145
- Add peer.service to http client instrumentations #2134
- Add automated login events to Symfony #2132 #2146
- Opt-in to flat service names #2163

### Changed
- Move all integrations to deferred loading #2153
- Reflect changes to datadog.version and datadog.env in existing spans #2165
- Evaluate the service name after the service mapping for a sampling decision #2166

### Fixed
- Add invalid regex handling for sampling rules #2160

### Internal Changes
- Add SpanData::peerServiceSources #2130
- Handle peer.service-related post-process in the extension #2135
- Enable instrumentation telemetry by default #2153

## Profiling

### Added
- doc(profiling): make phpinfo() output more helpful #2144
- timeline: add eval() timings #2150

### Fixed
- Explicit shutdown allocation profiling on fork() #2149
- Optimize event timestamp for timeline #2157

### Internal changes
- refactor(profiling): apply clippy suggestions #2141