contrib/push_locale: start using crowdin v2 API (instead of v1)

-----

closes https://github.com/spesmilo/electrum/issues/6936

Note: if we used the python crowdin client (https://github.com/crowdin/crowdin-api-client-python),
we would do something like this:

```
from crowdin_api import CrowdinClient
class MyCrowdinClient(CrowdinClient):
    TOKEN = ...
client = MyCrowdinClient()
with open(locale_file_name, 'rb') as f:
    resp = client.storages.add_storage(f)
    storage_id = resp['data']['id']
client.source_files.update_file(projectId=crowdin_project_id, storageId=storage_id, fileId=crowdin_file_id)
client.translations.build_crowdin_project_translation(projectId=crowdin_project_id)
```

.cirrus.yml

@@ -81,6 +81,7 @@ task:
   env:
     ELECTRUM_IMAGE: python:3.7
     ELECTRUM_REQUIREMENTS: contrib/requirements/requirements-travis.txt
+    # in addition, crowdin_api_key is set as an "override" in https://cirrus-ci.com/settings/...
   depends_on:
     - Tox Python 3.9
   only_if: $CIRRUS_BRANCH == 'master'

contrib/push_locale

@@ -1,8 +1,6 @@
 #!/usr/bin/env python3
 import os
 import subprocess
-import io
-import zipfile
 import sys
 
 try:
@@ -25,15 +23,12 @@ print("Found {} files to translate".format(len(files.splitlines())))
 # Generate fresh translation template
 if not os.path.exists('electrum/locale'):
     os.mkdir('electrum/locale')
-print('Generate template')
+print('Generating template...')
 cmd = 'xgettext -s --from-code UTF-8 --language Python --no-wrap -f app.fil --output=electrum/locale/messages.pot'
 subprocess.check_output(cmd, shell=True)
 
 os.chdir('electrum')
 
-crowdin_identifier = 'electrum'
-crowdin_file_name = 'files[electrum-client/messages.pot]'
-locale_file_name = 'locale/messages.pot'
 crowdin_api_key = None
 
 filename = os.path.expanduser('~/.crowdin_api_key')
@@ -44,16 +39,36 @@ if os.path.exists(filename):
 if "crowdin_api_key" in os.environ:
     crowdin_api_key = os.environ["crowdin_api_key"]
 
-if crowdin_api_key:
-    # Push to Crowdin
-    print('Push to Crowdin')
-    url = ('https://api.crowdin.com/api/project/' + crowdin_identifier + '/update-file?key=' + crowdin_api_key)
-    with open(locale_file_name, 'rb') as f:
-        files = {crowdin_file_name: f}
-        response = requests.request('POST', url, files=files)
-    print("", "update-file:", "-"*20, response.text, "-"*20, sep="\n")
-    # Build translations
-    print('Build translations')
-    response = requests.request('GET', 'https://api.crowdin.com/api/project/' + crowdin_identifier + '/export?key=' + crowdin_api_key)
-    print("", "export:", "-" * 20, response.text, "-" * 20, sep="\n")
+if not crowdin_api_key:
+    print('Missing crowdin_api_key. Cannot push.')
+    sys.exit(0)
+print('Found crowdin_api_key. Will push updated source-strings to crowdin.')
 
+crowdin_project_id = 20482  # for "Electrum" project on crowdin
+locale_file_name = "locale/messages.pot"
+crowdin_file_name = "messages.pot"
+crowdin_file_id = 68  # for "/electrum-client/messages.pot"
+global_headers = {"Authorization": "Bearer {}".format(crowdin_api_key)}
+
+# client.storages.add_storage(f)
+print(f"Uploading to temp storage...")
+url = f'https://api.crowdin.com/api/v2/storages'
+with open(locale_file_name, 'rb') as f:
+    headers = {**global_headers, **{"Crowdin-API-FileName": crowdin_file_name}}
+    response = requests.request("POST", url, data=f, headers=headers)
+    print("", "storages.add_storage:", "-" * 20, response.text, "-" * 20, sep="\n")
+    storage_id = response.json()["data"]["id"]
+
+# client.source_files.update_file(projectId=crowdin_project_id, storageId=storage_id, fileId=crowdin_file_id)
+print(f"Copying from temp storage and updating file in perm storage...")
+url = f'https://api.crowdin.com/api/v2/projects/{crowdin_project_id}/files/{crowdin_file_id}'
+headers = {**global_headers, **{"content-type": "application/json"}}
+response = requests.request("PUT", url, json={"storageId": storage_id}, headers=headers)
+print("", "source_files.update_file:", "-" * 20, response.text, "-" * 20, sep="\n")
+
+# client.translations.build_crowdin_project_translation(projectId=crowdin_project_id)
+print(f"Rebuilding translations...")
+url = f'https://api.crowdin.com/api/v2/projects/{crowdin_project_id}/translations/builds'
+headers = {**global_headers, **{"content-type": "application/json"}}
+response = requests.request("POST", url, headers=headers)
+print("", "translations.build_crowdin_project_translation:", "-" * 20, response.text, "-" * 20, sep="\n")