I would like the max upload size to be configurable

[ruudschilders]

Is your feature request related to a problem? Please describe.
A user wanted to import their .tar.gz file from another server, but the file was 40MB. The 'Import' button wouldn't work

Describe the solution you'd like
The MAX_FILE_SIZE_BYTES is currently hard-coded in bookwyrm.js, it would be nice if it's configurable in the .env file

Describe alternatives you've considered
I changed the value in bookwyrm,js but that will be overwritten at each update

Additional context
I am running Bookwyrm (https://bookwyrm.world) in docker.

[hughrun]

Max upload size should be controlled by DATA_UPLOAD_MAX_MEMORY_SIZE in Django - which as of a recent change is controlled by an env setting of DATA_UPLOAD_MAX_MEMORY_MiB in BookWyrm to make it easier for admins.

I didn't realise we had another totally different custom setting in the JS file. This seems unnecessary - Django will reject an upload that's too big with an appropriate error (see #3121).

@mouse-reeve looks like you put this in with #1165 - do you remember why?