Allow default web route to be configured like all other route (allow specify method, auth etc.)

[t83714]

Allow default web route to be configured like all other web routes (allow specify methods, auth etc.)

2928 already made webRoutes be able to configure with more options (e.g. auth, method etc).

However, the default web route still use (and the only one) createGenericProxy

https://github.com/magda-io/magda/blob/d3f85b69e69f325f7712b412a63336299286372f/magda-gateway/src/buildApp.ts#L270

Due to security concerns, we probably can't hardcode createGenericProxy to proxy all methods and should let the user to config instead.

Also, we will want the helm config to be compatible with the existing config (easier to upgrade existing sites).

Thus, propose the following solution:

Possible Solution:

• By default, the string web field config here still works as before. i.e.
  • Assume only proxy GET method & no auth etc.
• accept an optional new defaultWebRouteConfig section that allows to config all proxy target options. i.e.:
  • methods: array of string. "all" means all methods
  • auth: whether this target requires session. Otherwise, session / password related midddleware won't run
  • redirectTrailingSlash: make /xxx auto redirect to /xxxx/
  • statusCheck: check target's live status from the gateway
  • proxy target URL should still be configured via web config field above
• Remove createGenericProxy from codebase (only default web route uses it now) and use createGenericProxyRouter instead for proxying default web route.

[mwu2018]

Removing createGenericProxy from codebase -- simplicity is good.

[t83714]

Removing createGenericProxy from codebase -- simplicity is good.

Yeah~ I recently added createGenericProxyRouter just for it.

it (createGenericProxyRouter) works as a more consistent way to proxy either API routes or web routes and it also helped to reduce some code duplication.