Changes
### Added
- (PHP 5) Add zai config, internal spans, and exception handling (#1339)
- (PHP 7, 8) Add mongodb instrumentation (#1345)
- PHP installation script (beta) (#1335)
### Changed
- (PHP 5, 7) Move _dd.origin handling to internal #1347
### Fixed
- (PHP 7, 8) Fix exception handling with opcache cfg optimization enabled (#1344)
- (PHP 7, 8) Fix memory leaks in curl and error handling (#1350)
- Use ObjectKVStore in place of internal registry to store PDO connection parameters (#1355)