Rework permission checks #1145

Job	Run time
Clippy	48s
Build docs	1m 21s
Rustfmt	12s
Test (MSRV)	1m 17s
Test (stable)	2m 2s
Test (beta)	2m 2s
Test (nightly)	1m 39s
Test (macOS)	1m 27s
Test (Windows)	4m 8s
Test (no features)	1m 11s
Test (all features - simdjson, cargo test --all-features --lib --tests --examples)	1m 15s
Test (native TLS, cargo test --all-features --features serenity/native_tls_backend --lib --tests ...	1m 23s
	18m 45s

Provide feedback