Move to Bintray

Fixes #2 (closed)

.ci-templates/conan.yml

 .build-template:
     variables:
-        CONAN_USERNAME: "ptr-project+sqlite_utils"
+        CONAN_USERNAME: "ptr"
         CONAN_CHANNEL: "testing"
         CONAN_ARCHS: "x86_64"
-        CONAN_UPLOAD: "https://gitlab.com/api/v4/packages/conan"
+        CONAN_UPLOAD: "https://api.bintray.com/conan/ptr-project/conan"
+        CONAN_UPLOAD_RETRY: 3
         CONAN_STABLE_BRANCH_PATTERN: "stable/*"
-        # Add conan center with additional slash such that it is different from the
-        # default one. With this we can reorder the default repo in front of our
-        # upload repo.
-        # Otherwise, checking for packages without channel/user on gitlab will
-        # currently fail.
-        CONAN_REMOTES: "https://conan.bintray.com/, https://gitlab.com/api/v4/packages/conan"
+        CONAN_LOGIN_USERNAME: ${BINTRAY_USER}
+        CONAN_PASSWORD: ${BINTRAY_PASSWORD}
     before_script:
         - sudo pip install --upgrade conan_package_tools
         - conan user