R18 is shutting down, JAVR scraped scenes need a migration

[vt-idiot]

Which means images, cover_url, and scene_url for any JAVR scraped scenes will break.

FANZA is not shutting down in Japan, and their URLs for images are identical after the first slash - I was able to test the following manually on my database, and it seems like all of the images still load:

UPDATE scenes
SET
	images = REPLACE(images, 'https://pics.r18.com/', 'https://pics.dmm.co.jp/'),
	cover_url = REPLACE(cover_url, 'https://pics.r18.com/', 'https://pics.dmm.co.jp/');

Alternatively, if you also want to change the links to the scenes themselves, although they will be entirely in Japanese:

UPDATE scenes
SET
	images = REPLACE(images, 'https://pics.r18.com/', 'https://pics.dmm.co.jp/'),
	cover_url = REPLACE(cover_url, 'https://pics.r18.com/', 'https://pics.dmm.co.jp/'),
	scene_url = REPLACE(scene_url, 'https://www.r18.com/videos/vod/movies/detail/-/', 'https://www.dmm.co.jp/digital/videoa/-/detail/=/c');

That extra line will change a link to e.g. https://www.r18.com/videos/vod/movies/detail/-/id=wavr00066/ to https://www.dmm.co.jp/digital/videoa/-/detail/=/cid=wavr00066/

I am not 100% sure how migrations work, but I'll open a pull request for one that tries to do all of the above.