[public-api] Refactor to use connect handlers

[easyCZ]

Description

In this PR, we 1-1 map the old implementation in gRPC to the new implementation with Connect. Changes are deliberately not made to streamline the tests and simplify to keep the PR cleaner.

In general, the changes are the following (see docs)

1. Use the generated ServiceHandlers
2. Wrap requests and responses in connect.NewRequest or connect.NewResponse
3. Use Connects error codes
4. Use HTTP server in tests

This PR also changes default routing of api.<domain> requests to the HTTP server, this has the following effect:

• Connect handlers handle both gRPC and HTTP traffic - this is fine, as Connect is designed for this
• Depending on the rollout sequencing, there can be a brief period where requests would fail. This is OK, as we don't get any traffic on this yet anyway.

Related Issue(s)

• Depends on [public-api] Authentication interceptors for connect API #13693

How to test

Unit tests

1. Log in to preview and run the following in the console to get an access token:

	await window._gp.gitpodService.server.generateNewGitpodToken({ type: 1, scopes: ["function:getGitpodTokenScopes",
	"function:getWorkspace",
	"function:getWorkspaces",
	"function:listenForWorkspaceInstanceUpdates",
	"resource:default",]})

To make subsequent steps readily runnable, export the token in your shell:

export BEARER_TOKEN="<token>"

Validate we can reach the new APIs over cURL:

curl \
    --header 'Content-Type: application/json' \
    --header 'Authorization: Bearer $BEARER_TOKEN' \
    --data '{}' \
    https://api.mp-public-ca4417e0d2.preview.gitpod-dev.com/gitpod.v1.WorkspacesService/ListWorkspaces | jq

{}

We're doing a list call, and we don't have workspaces so an empty list response is expected.

Validate we can reach the APIs using a gRPC client

gpctl api workspaces list --address api.mp-public-ca4417e0d2.preview.gitpod-dev.com:443 --token $BEARER_TOKEN 

ID        Owner        ContextURL

Again, we're not getting any workspaces back because we've not started any but the important part is we're not getting an error.

Release Notes

NONE

Documentation

Werft options:

• /werft with-local-preview
  If enabled this will build install/preview
• /werft with-preview
• /werft with-integration-tests=all
  Valid options are all, workspace, webapp, ide

[werft-gitpod-dev-com]

started the job as gitpod-build-mp-public-api-use-connect-instead-of-grpc.3 because the annotations in the pull request description changed
(with .werft/ from main)

[easyCZ]

Diff shows wierd. This test is removed as it's already tested in TestPublicAPIServer_v1_WorkspaceService

[easyCZ]

Connect doesn't define the default Error Code value as OK, so we have to do this extra check..

[easyCZ]

Was not correctly adding the Bearer prefix, and we weren't also correctly checking for it server side.

[easyCZ]

Closing as werft got into an inconcistent state. Replacement PR is here