Extract backend repository from nodeinfo

Also removes extractCommit, could be kept when the forge is git.pleroma.social

Partial fix of https://git.pleroma.social/pleroma/pleroma-fe/-/issues/1283

test/unit/specs/services/version/version.service.spec.js

@@ -1,11 +0,0 @@
-import { extractCommit } from 'src/services/version/version.service.js'
-
-describe('extractCommit', () => {
-  it('return short commit hash following "-g" characters', () => {
-    expect(extractCommit('1.0.0-45-g5e7aeebc')).to.eql('5e7aeebc')
-  })
-
-  it('return short commit hash without branch name', () => {
-    expect(extractCommit('1.0.0-45-g5e7aeebc-branch')).to.eql('5e7aeebc')
-  })
-})