sys/config: config state endpoint (#7424)

* sys/config: initial work on adding config state endpoint

* server/config: add tests, fix Sanitized method

* thread config through NewTestCluster's config to avoid panic on dev modes

* properly guard endpoint against request forwarding

* add http tests, guard against panics on nil RawConfig

* ensure non-nil rawConfig on NewTestCluster cores

* update non-forwarding logic

* fix imports; use no-forward handler

* add missing config test fixture; update gitignore

* return sanitized config as a map

* fix test, use deep.Equal to check for equality

* fix http test

* minor comment fix

* config: change Sanitized to return snake-cased keys, update tests

* core: hold rlock when reading config; add docstring

* update docstring

command/server.go

@@ -668,6 +668,7 @@ func (c *ServerCommand) Run(args []string) int {
 	}
 
 	coreConfig := &vault.CoreConfig{
+		RawConfig:                 config,
 		Physical:                  backend,
 		RedirectAddr:              config.Storage.RedirectAddr,
 		StorageType:               config.Storage.Type,
@@ -973,7 +974,7 @@ CLUSTER_SYNTHESIS_COMPLETE:
 		}
 		props["max_request_size"] = fmt.Sprintf("%d", maxRequestSize)
 
-		var maxRequestDuration time.Duration = vault.DefaultMaxRequestDuration
+		maxRequestDuration := vault.DefaultMaxRequestDuration
 		if valRaw, ok := lnConfig.Config["max_request_duration"]; ok {
 			val, err := parseutil.ParseDurationSecond(valRaw)
 			if err != nil {
@@ -1415,6 +1416,8 @@ CLUSTER_SYNTHESIS_COMPLETE:
 				goto RUNRELOADFUNCS
 			}
 
+			core.SetConfig(config)
+
 			if config.LogLevel != "" {
 				configLogLevel := strings.ToLower(strings.TrimSpace(config.LogLevel))
 				switch configLogLevel {