refactor: introduce `AppBuilder` trait #16369

Job	Run time
Check (windows-2022)	6m 11s
Check (ubuntu-20.04)	2m 5s
Check typos and docs	6s
Clippy	3m 12s
Build GreptimeDB binaries (ubuntu-20.04)	4m 28s
Rustfmt	25s
Check License Header	1m 18s
coverage	0s
Toml Check	28s
Sqlness Test (ubuntu-20.04)	2m 15s
Unstable Fuzz Test (unstable_fuzz_create_table_standalone)	13m 35s
Fuzz Test (fuzz_create_table)	4m 56s
Fuzz Test (fuzz_alter_table)	4m 49s
Sqlness Test with Kafka Wal (ubuntu-20.04)	3m 1s
Fuzz Test (fuzz_create_database)	5m 10s
Fuzz Test (fuzz_create_logical_table)	4m 51s
Fuzz Test (fuzz_alter_logical_table)	4m 58s
Fuzz Test (fuzz_insert)	5m 0s
Fuzz Test (fuzz_insert_logical_table)	5m 2s
	1h 11m 50s

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