fsnotify events should logged as --verbose output

[jimafisk]

Currently when you add, edit/save, delete a file while running the webserver, it rebuilds the site and you see logging information about which fsnotify events were triggered:

File create detected: fsnotify.Event{Name:"content/events", Op:0x1}

File create detected: fsnotify.Event{Name:"layout/content/events.svelte", Op:0x1}

Or

File delete detected: fsnotify.Event{Name:"layout/content/4913", Op:0x4}

File rename detected: fsnotify.Event{Name:"layout/content/index.svelte", Op:0x8}

File create detected: fsnotify.Event{Name:"layout/content/index.svelte", Op:0x1}

File write detected: fsnotify.Event{Name:"layout/content/index.svelte", Op:0x2}

File delete detected: fsnotify.Event{Name:"layout/content/index.svelte~", Op:0x4}

We should use the build.Log utility to only show these messages if the --verbose flag is passed, e.g. plenti serve -v