feat: add Query Builder `explain()` (#10238) #15244

Job	Run time
Setup PHP Version for Code Coverage	2s
Others (8.4) / Sanity Tests	1m 30s
Others (8.3) / Sanity Tests	1m 37s
Others (8.2) / Sanity Tests	2m 57s
Others (8.5) / Sanity Tests	1m 47s
SeparateProcess (8.4) / tests	1m 59s
SeparateProcess (8.5) / tests	2m 18s
CacheLive (8.4) / Cache Live Tests	1m 26s
CacheLive (8.3) / Cache Live Tests	1m 29s
SeparateProcess (8.3) / tests	2m 13s
CacheLive (8.2) / Cache Live Tests	1m 46s
DatabaseLive (8.5, MySQLi, 8.0) / tests	3m 57s
SeparateProcess (8.2) / tests	1m 53s
DatabaseLive (8.3, Postgre, 8.0) / tests	1m 53s
DatabaseLive (8.2, MySQLi, 5.7) / tests	3m 16s
CacheLive (8.5) / Cache Live Tests	1m 33s
DatabaseLive (8.4, MySQLi, 8.0) / tests	4m 10s
DatabaseLive (8.5, Postgre, 8.0) / tests	1m 49s
DatabaseLive (8.3, OCI8, 8.0) / tests	7m 46s
DatabaseLive (8.4, Postgre, 8.0) / tests	1m 38s
DatabaseLive (8.3, MySQLi, 8.0) / tests	4m 9s
DatabaseLive (8.2, SQLite3, 8.0) / tests	2m 21s
DatabaseLive (8.2, SQLSRV, 8.0) / tests	6m 5s
DatabaseLive (8.5, OCI8, 8.0) / tests	7m 58s
DatabaseLive (8.2, Postgre, 8.0) / tests	2m 44s
DatabaseLive (8.3, SQLSRV, 8.0) / tests	7m 20s
DatabaseLive (8.4, SQLSRV, 8.0) / tests	5m 37s
DatabaseLive (8.3, SQLite3, 8.0) / tests	1m 21s
DatabaseLive (8.4, OCI8, 8.0) / tests	7m 26s
DatabaseLive (8.5, SQLite3, 8.0) / tests	1m 9s
DatabaseLive (8.2, OCI8, 8.0) / tests	9m 31s
DatabaseLive (8.5, SQLSRV, 8.0) / tests	5m 26s
DatabaseLive (8.4, SQLite3, 8.0) / tests	58s
DatabaseLive (8.2, MySQLi, 8.0) / tests	4m 37s
Upload coverage results to Coveralls / coveralls	54s
	1h 54m 35s

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