internal: implement path normalization w/ configurable rules

Strips query strings and URL fragmenets, prevents unbounded Prometheus
metrics by normalizing paths like:

- `/users/12345/profile -> /users/:id/profile`
- `/page?utm_source=twitter -> /page`
- `/a/../b -> /b`

etc.

Signed-off-by: NotAShelf <raf@notashelf.dev>
Change-Id: I72f2fa2452f4666567143d052b5716476a6a6964

internal/config/config.go

@@ -37,6 +37,7 @@ type PathConfig struct {
 	StripFragment           bool `yaml:"strip_fragment"`
 	CollapseNumericSegments bool `yaml:"collapse_numeric_segments"`
 	MaxSegments             int  `yaml:"max_segments"`
+	NormalizeTrailingSlash  bool `yaml:"normalize_trailing_slash"`
 }
 
 // Cardinality limits