feat: add --experiments flag to replace --experimental (#5767)

- Deprecates the --experimental flag
- Adds a new flag --experiments which supports passing multiple comma-separated values or a wildcard value.
- Exposes a new endpoint /api/v2/experiments that returns the list of enabled experiments.
- Deprecates the field Features.Experimental in favour of this new API.
- Updates apidocgen to support type aliases (shoutout to @mtojek).
- Modifies apitypings to support generating slice types.
- Updates develop.sh to pass additional args after -- to $CODERD_SHIM.

coderd/experiments.go

@@ -0,0 +1,19 @@
+package coderd
+
+import (
+	"net/http"
+
+	"github.com/coder/coder/coderd/httpapi"
+)
+
+// @Summary Get experiments
+// @ID get-experiments
+// @Security CoderSessionToken
+// @Produce json
+// @Tags General
+// @Success 200 {array} codersdk.Experiment
+// @Router /experiments [get]
+func (api *API) handleExperimentsGet(rw http.ResponseWriter, r *http.Request) {
+	ctx := r.Context()
+	httpapi.Write(ctx, rw, http.StatusOK, api.Experiments)
+}