Add case-insensitive routing

[tdotclare]

Allows configuring case-insensitive routing (#2354).

// Enables case-insensitive routing.
// Defaults to false.
app.routes.caseInsensitive = true

[tdotclare]

Someone asked yesterday on Discord about case insensitive routing. I don't know that I'd ever actually ADVISE someone to do this, but since TrieRouter can do it, this PR adds a configurable setting to app.routes so DefaultResponder can grab it and pass it to TrieRouter.

Whether this is a Good Idea is up for debate and feel free to skip approving it if not, hah

[0xTim]

I'm +1 for at least exposing this

[tanner0101]

+1 to adding this, thanks! Would you mind add a note to https://github.com/vapor/docs/blob/master/4.0/docs/routing.md as well?

[tanner0101]

Please format the PR title / body as release notes, too.

[tdotclare]

Initial PR comments reproduced:

• Adds Application.Routes.caseInsensitive flag to allow configuring case insensitive routes prior to boot (defaults to false)
• DefaultResponder will configure TrieRouter appropriately if set to true
• Appropriate test

Allows configuring Vapor to use case insensitive route handling

EG:

app.routes.caseInsensitive = true
app.routes.get("foo") {...}
app.run()
...
myserver.com/foo -> "200 OK"
myserver.com/FOO -> "200 OK"

Note that case-insensitive routing is somewhat less performant, and only applies to constant PathComponents - eg: app.routes.get("foo", ":id") maintains case of URL request to parameter id, so myserver.com/FoO/uSeRiD would correctly hit the registered route handler but within the route handler, the value of id will still be uSeRiD.

[tanner0101]

These changes are now available in 4.12.0

[maclee99]

missing an "I" in the app.routes.caseInsenstive