refactor(healthcheck): streamline health check configuration and defaults

- Moved health check constants from common package alongside type definition.
- Updated health check configuration to use struct directly instead of pointers.
- Introduced global default health check config

internal/watcher/health/monitor/http.go

@@ -29,7 +29,7 @@ var pinger = &fasthttp.Client{
 	NoDefaultUserAgentHeader: true,
 }
 
-func NewHTTPHealthMonitor(url *url.URL, config *types.HealthCheckConfig) *HTTPHealthMonitor {
+func NewHTTPHealthMonitor(url *url.URL, config types.HealthCheckConfig) *HTTPHealthMonitor {
 	mon := new(HTTPHealthMonitor)
 	mon.monitor = newMonitor(url, config, mon.CheckHealth)
 	if config.UseGet {