feat: Expose web ui router for external server, and switch to *http.ServeMux from gocraft/web

[vin-rmdn]

Resolves #43

[vin-rmdn]

Action items from discussion with @chopraanmol1 via DM:

• Do not expose server’s router, this looks like a hack. Instead, let’s create a new method NewRouter which returns *web,Router and NewServer can call the same method internally
  • For new router constructor, let’s accept dependency and build client
  • Please check, on the web UIs what field from Server is used, and add that accordingly to the router constructor
    • I'm opting to have NewServer depend on NewRouter instead
• On web side let’s try to use relative path to avoid the need of knowing or replacing path prefix.
• For context struct, since we’re having router constructor, let’s change the field inside context from Server to Client

Proposed structure:

func NewServer(namespace string, pool *redis.Pool, hostPort string) *Server {
	...
	client = work.NewClient(namespace, pool)
	router = buildRouter(client)
	...
}

func NewRouter(namespace string, pool *redis.Pool) *web.Router {
	...
	client = work.NewClient(namespace, pool)
	return buildRouter(client)	
}

func buildRouter(*work.Client) *web.Router {
	....
}

EDIT 2024/09/30: relative path is doable

[vin-rmdn]

More action items with @chopraanmol1

• Let's do relative path for our JS-based worker UI (it will work if we do /prefix/ instead of /prefix) and replace it for all HTML and JS urls
• Remove mention of path prefix
  • on HTML and JS
  • on Go code
    • *Currently not possible due to web.Router needing the specific prefix for subrouting, else the router will return 404
• Revert the templating change
• Refactoring changes suggestions:
  • Rename NewRouter to BuildRouter
  • Instead of doing RouterOptions, let's pass *web.Router, which removes any path-specific code from the library
    • Adding *web.Router as parameter will explicitly state dependency of gocraft/web for the router factory, and this will break compatibility with other routers (e.g., Mux, Echo) and require dependent service to use another routing library as well
  • For this new method, add comments that for a trailing / is needed for the webui to work as expected
• To simplify review, move back few of the file back to webui.go: moved context back to webui file.