Add HTTP method matching to resource rules

Resolves #1408.

A rule with match "METHOD" carries a comma-separated list of HTTP
methods in its value, e.g. "POST,PUT", and applies when the request
method is in that list. This makes it possible to leave GET public
while sending POST and PUT to auth, which rules could not express
before because both share the same path.

No new columns: the methods live in the existing rule value, so this
needs no migration and every existing rule keeps working unchanged.

The UI offers the ten registered methods. Blueprints and the API
accept any method token, so extension methods such as the WebDAV verbs
can be targeted too, and the UI preserves them when a rule set that
way is edited later.

server/lib/validators.test.ts

@@ -1,9 +1,10 @@
 import {
     getResourceRuleValueValidationError,
     isValidDomain,
-    isValidUrlGlobPattern
+    isValidUrlGlobPattern,
+    parseHttpMethodList
 } from "./validators";
-import { assertEquals } from "@test/assert";
+import { assertEquals, assertEqualsObj } from "@test/assert";
 
 function runTests() {
     console.log("Running domain validation tests...");
@@ -295,6 +296,44 @@ function runTests() {
         "Invalid ASN should return an error"
     );
 
+    // HTTP method validation tests
+    assertEquals(
+        getResourceRuleValueValidationError("METHOD", "POST"),
+        null,
+        "Single HTTP method should be valid"
+    );
+    assertEquals(
+        getResourceRuleValueValidationError("METHOD", " post , Put "),
+        null,
+        "Method list should be valid with mixed case and whitespace"
+    );
+    assertEquals(
+        getResourceRuleValueValidationError("METHOD", "PROPFIND"),
+        null,
+        "Extension methods such as the WebDAV verbs should be valid"
+    );
+    assertEquals(
+        getResourceRuleValueValidationError("METHOD", ""),
+        "Invalid HTTP method provided",
+        "Empty method list should return an error"
+    );
+    assertEquals(
+        getResourceRuleValueValidationError("METHOD", ",,"),
+        "Invalid HTTP method provided",
+        "Method list of only separators should return an error"
+    );
+    assertEquals(
+        getResourceRuleValueValidationError("METHOD", "GET POST"),
+        "Invalid HTTP method provided",
+        "Space separated methods should return an error"
+    );
+
+    assertEqualsObj(
+        parseHttpMethodList(" get ,post, "),
+        ["GET", "POST"],
+        "Method list should be normalized to uppercase without empty entries"
+    );
+
     console.log("All tests passed!");
 }