Opening secretstorage not detected if closed during startup

[samuel-w]

Describe the bug
Opening secretstorage after startup does not result in Vorta switching to it, instead prefering VortaDBKeyring.

To Reproduce
Steps to reproduce the behavior:

1. Start Vorta with secretstorage fully closed
2. Open the secretstorage program
3. Do something that uses the keyring

Result
It uses VortaDBKeyring, and never VortaSecretStorageKeyring

Recommended Solution
This is caused by the keyring getting set once at runtime keyring = VortaKeyring.get_keyring(), resulting in it never detecting a new keyring.
Remove 'keyring' from utils, and just call VortaKeyring.get_keyring() every time you want to get or set a password.

Desktop (please complete the following information):

• OS: Ubuntu 20.04
• Vorta: Latest master

Additional context

2020-09-04 15:39:23,498 - vorta.i18n - DEBUG - Loading translation failed for ['en', 'en-US', 'en-Latn-US'].
2020-09-04 15:39:23,507 - apscheduler.scheduler - INFO - Scheduler started
2020-09-04 15:39:23,891 - vorta.borg.borg_thread - INFO - Running command /home/user/.local/bin/borg --version
2020-09-04 15:39:33,040 - vorta.borg.borg_thread - DEBUG - Using VortaDBKeyring keyring to store passwords.
2020-09-04 15:39:33,051 - vorta.borg.borg_thread - INFO - Running command /home/user/.local/bin/borg info --info --json --log-json /mnt/data/borg-repokey
2020-09-04 15:39:33,618 - vorta.borg.borg_thread - DEBUG - Using VortaDBKeyring keyring to store passwords.
2020-09-04 15:39:33,628 - vorta.borg.borg_thread - INFO - Running command /home/user/.local/bin/borg list --info --log-json --json /mnt/data/borg-repokey
2020-09-04 15:40:04,325 - vorta.borg.borg_thread - DEBUG - Using VortaDBKeyring keyring to store passwords.
2020-09-04 15:40:04,335 - vorta.borg.borg_thread - INFO - Running command /home/user/.local/bin/borg info --info --json --log-json /tmp/asdf2
2020-09-04 15:40:04,641 - vorta.borg.borg_thread - ERROR - /tmp/asdf2 is not a valid repository. Check repo config.
2020-09-04 15:40:06,554 - vorta.borg.borg_thread - DEBUG - Using VortaDBKeyring keyring to store passwords.
2020-09-04 15:40:06,563 - vorta.borg.borg_thread - INFO - Running command /home/user/.local/bin/borg info --info --json --log-json /tmp/asdf2
2020-09-04 15:40:06,848 - vorta.borg.borg_thread - ERROR - /tmp/asdf2 is not a valid repository. Check repo config.
2020-09-04 15:40:07,693 - vorta.borg.borg_thread - DEBUG - Using VortaDBKeyring keyring to store passwords.
2020-09-04 15:40:07,703 - vorta.borg.borg_thread - INFO - Running command /home/user/.local/bin/borg info --info --json --log-json /tmp/asdf2
2020-09-04 15:40:08,001 - vorta.borg.borg_thread - ERROR - /tmp/asdf2 is not a valid repository. Check repo config.

Here I open secretstorage

2020-09-04 15:40:20,177 - vorta.borg.borg_thread - DEBUG - Using VortaDBKeyring keyring to store passwords.
2020-09-04 15:40:20,186 - vorta.borg.borg_thread - INFO - Running command /home/user/.local/bin/borg init --info --log-json --encryption=repokey-blake2 /tmp/asdf2
2020-09-04 15:40:20,474 - vorta.borg.borg_thread - INFO - Initializing repository at "/tmp/asdf2"
2020-09-04 15:40:20,513 - vorta.borg.borg_thread - INFO - Key in "<Repository /tmp/asdf2>" created.
2020-09-04 15:40:20,513 - vorta.borg.borg_thread - INFO - Keep this key safe. Your data will be inaccessible without it.
2020-09-04 15:40:20,546 - vorta.borg.borg_thread - INFO - Synchronizing chunks cache...
2020-09-04 15:40:20,546 - vorta.borg.borg_thread - INFO - Archives: 0, w/ cached Idx: 0, w/ outdated Idx: 0, w/o cached Idx: 0.
2020-09-04 15:40:20,547 - vorta.borg.borg_thread - INFO - Done.
2020-09-04 15:40:20,571 - vorta.borg.borg_thread - WARNING -