feat: use go1.16 and resources embedding (#235)

* feat: use go1.16 embedding for resources

We want to embed everything that can be easily embedded. We should, at a
minimum, replace the downloading of resources and bindata.

Ref: https://github.com/ooni/probe/issues/1367.

* fix: get rid of bindata and use go embed instead

* fix: start unbreaking some automatic tests

* fix: fetch resources as part of the mobile build

* fix: convert more stuff to go1.16

I still expect many breakages, but we'll fix them.

* fix: make the windows CI green

* fix: get resources before running QA

* fix: go1.16 uses modules by default

* hopefully fix all other outstanding issues

* fix(QA/telegram.py): add another DC IP address

* Apply suggestions from code review

build-ios.bash

@@ -3,9 +3,8 @@ set -e
 topdir=$(cd $(dirname $0) && pwd -P)
 set -x
 export PATH=$(go env GOPATH)/bin:$PATH
-export GO111MODULE=off
 go get -u golang.org/x/mobile/cmd/gomobile
 gomobile init
-export GO111MODULE=on
 output=MOBILE/ios/oonimkall.framework
+go run ./internal/cmd/getresources
 gomobile bind -target=ios -o $output -ldflags="-s -w" ./pkg/oonimkall