fast base32 encoding into uint32 and uint64

$ go test -bench=. -benchmem .
goos: darwin
goarch: arm64
pkg: github.com/ndx-technologies/base32quant
cpu: Apple M3 Max
BenchmarkUint32_AppendText-16                   626010067                1.774 ns/op           0 B/op          0 allocs/op
BenchmarkUint32_MarshalText-16                  149704831                8.002 ns/op           8 B/op          1 allocs/op
BenchmarkUint32_MarshalText_standard-16         88877643                13.27 ns/op            8 B/op          1 allocs/op
BenchmarkUint32_UnmarshalText-16                211679582                5.688 ns/op           0 B/op          0 allocs/op
BenchmarkUint32_UnmarshalText_standard-16       55846422                21.13 ns/op            8 B/op          1 allocs/op
BenchmarkUint64_AppendText-16                   432771045                2.777 ns/op           0 B/op          0 allocs/op
BenchmarkUint64_MarshalText-16                  100000000               10.52 ns/op           16 B/op          1 allocs/op
BenchmarkUint64_MarshalText_standard-16         80863894                14.53 ns/op            8 B/op          1 allocs/op
BenchmarkUint64_UnmarshalText-16                100000000               12.05 ns/op            0 B/op          0 allocs/op
BenchmarkUint64_UnmarshalText_standard-16       36515414                32.12 ns/op           16 B/op          1 allocs/op
PASS
ok      github.com/ndx-technologies/base32quant 11.989s