refactor: move getPreset into lib/config/preset/ (#5578)

lib/config/presets/__fixtures__/renovate-config-default.json

lib/config/presets/__fixtures__/renovate-config-group.json

...config/presets/__fixtures__/renovate-config-ikatyang.json

...config/presets/__fixtures__/renovate-config-monorepo.json

...config/presets/__fixtures__/renovate-config-packages.json

lib/config/presets/__snapshots__/index.spec.ts.snap

lib/config/presets/__snapshots__/npm.spec.ts.snap

lib/config/presets/common.ts

lib/config/presets/github.spec.ts

lib/config/presets/github.ts

lib/config/presets/gitlab.spec.ts

lib/config/presets/gitlab.ts

lib/config/presets/index.spec.ts

lib/config/presets/index.ts

lib/config/presets/npm.spec.ts

lib/config/presets/npm.ts

lib/datasource/common.ts

lib/datasource/github/index.spec.ts

lib/datasource/github/index.ts

lib/datasource/gitlab/index.spec.ts