feat: rust toolchain file #1859

Job	Run time
Build `sea-query-binder` (async-std, rustls)	4m 57s
Build `sea-query`	1m 43s
Clippy	1m 49s
Build `sea-query-postgres`	1m 57s
Build `sea-query-rusqlite`	1m 27s
Rustfmt	19s
Unit Test	3m 11s
Derive Tests	1m 17s
MariaDB (10.6, sqlx_mysql)	1m 49s
MySQL (8, sqlx_mysql)	1m 57s
MySQL (5.7, sqlx_mysql)	2m 4s
SQLite (rusqlite)	53s
SQLite (sqlx_sqlite)	1m 55s
PostgreSQL (14.4, postgres)	1m 41s
PostgreSQL (14.4, sqlx_postgres)	2m 35s
PostgreSQL (13.7, postgres)	1m 36s
PostgreSQL (13.7, sqlx_postgres)	1m 56s
PostgreSQL (12.11, postgres)	1m 26s
PostgreSQL (12.11, sqlx_postgres)	2m 18s
	36m 50s

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