FID as main identifier, not nickname

Because user can don't have a game so no nickname, but his
FDEV tokens still suits for not CAPI requests (i.e. squadrons api)

scripts/migrate_db_0.2_to_0.3.py

@@ -0,0 +1,52 @@
+import sqlite3
+import capi
+
+db = sqlite3.connect('companion-api.sqlite')
+
+
+backup_table_request = "ALTER TABLE authorizations RENAME TO authorizations_bak;"
+
+restore_table_request = """
+INSERT INTO authorizations (
+    code_verifier, 
+    state, 
+    timestamp_init, 
+    code, 
+    access_token, 
+    refresh_token, 
+    expires_in, 
+    timestamp_got_expires_in, 
+    nickname, 
+    refresh_tries,
+    usages
+)
+SELECT 
+    code_verifier, 
+    state, 
+    timestamp_init, 
+    code, 
+    access_token, 
+    refresh_token, 
+    expires_in, 
+    timestamp_got_expires_in, 
+    nickname, 
+    refresh_tries,
+    usages 
+FROM authorizations_bak;
+"""
+
+drop_old_table_request = "drop table authorizations_bak;"
+
+with db:
+    db.execute(backup_table_request)
+    db.execute(capi.sqlite_requests.schema)
+    db.execute(restore_table_request)
+    db.execute(drop_old_table_request)
+
+db.close()  # schema migration ended, begin inserting fids
+
+all_records = capi.capi_authorizer.list_all_records()
+for record in all_records:
+    if record['fid'] is None and record['nickname'] is not None:
+        fid = capi.utils.get_fid(record['access_token'])
+        capi.capi_authorizer.model.set_fid(fid, record['state'])