Use dependency injection for redirect classes

Assigning to myself as I'm triaging all RTBC issues.

Thanks, everyone, for the hard work for some time to get this patch in order.

1. Regarding the t() in #52, we can create a new issue for that. Also, coding standard changes that are unrelated to this issue can be left out. I didn't see any obvious ones in this patch but did in the one in 2 below.

2. This related patch should be included here IMO (see comment #6 for an explanation):

📌 Use dependency injection on redirect\Form\RedirectForm Postponed

3. The patch needs a reroll:

Kristens-MacBook-Pro:redirect kristenpol$ patch -p1 < 22.diff 
patching file modules/redirect_404/redirect_404.services.yml
patching file modules/redirect_404/src/SqlRedirectNotFoundStorage.php
patching file modules/redirect_404/tests/src/Unit/SqlRedirectNotFoundStorageTest.php
Hunk #3 FAILED at 44.
Hunk #4 succeeded at 51 (offset -2 lines).
Hunk #5 succeeded at 61 (offset -2 lines).
Hunk #6 succeeded at 76 (offset -2 lines).
1 out of 6 hunks FAILED -- saving rejects to file modules/redirect_404/tests/src/Unit/SqlRedirectNotFoundStorageTest.php.rej
patching file redirect.services.yml
patching file src/EventSubscriber/RedirectRequestSubscriber.php
patching file src/Form/RedirectForm.php
patching file src/Form/RedirectSettingsForm.php
patching file src/Plugin/Field/FieldWidget/RedirectSourceWidget.php
Hunk #1 succeeded at 3 with fuzz 2 (offset -1 lines).
Hunk #2 succeeded at 33 (offset -1 lines).
Hunk #3 succeeded at 122 (offset -1 lines).
Hunk #4 succeeded at 138 (offset -1 lines).
patching file src/RedirectChecker.php
Hunk #1 FAILED at 4.
1 out of 2 hunks FAILED -- saving rejects to file src/RedirectChecker.php.rej
patching file src/RedirectRepository.php
patching file tests/src/Unit/RedirectRequestSubscriberTest.php
Hunk #1 succeeded at 14 with fuzz 2 (offset -1 lines).
Hunk #2 succeeded at 155 (offset -9 lines).
Hunk #3 succeeded at 166 (offset -9 lines).

4. Please don't add company specific tags unless it's around a public event.

5. Hiding patches since we are using an MR now.

Hi I rerrolled please revise

timestamp is an unusual name for the time server, core uses just $time.

MR is ready to review.
Thanks!!