Improve trace secret masking with x/text/transform

What does this MR do?

Improves trace performance by using efficient text transforms for masking secrets.

Why was this MR needed?

• Improves performance
• Will allow us to scrub URLs with another transformer implemenation. We currently use regex to do this and it is incredibly slow.
• Fixes an issue where a secret would not be masked if it duplicated the first character (ie. ssecret).

Old benchmarks

BenchmarkBuffer10k-16    	      99	 115428652 ns/op	  17.33 MB/s	10407127 B/op	  190037 allocs/op

New benchmarks

BenchmarkBuffer10k-16    	     307	  39174771 ns/op	  51.05 MB/s	    9416 B/op	      24 allocs/op

What's the best way to test this MR?

Previous test traces continue to work. The new masking functionality has an array of new tests.

go test ./helpers/trace

What are the relevant issue numbers?

closes #16705 (closed)