Add bulk upload of pics for rentals

[ptkato]

this is already the case, you can pick multiple images for uploading

[jappeace]

I get 413 entity to large when wanting to upload 23 pics:

[ptkato]

Ah, I see, well, the default max size is 2 megabytes, what would be a desired max size for uploading, if having a max size at all?

[jappeace]

if we could support 23 files, it'd be good, i guess bumping it to 30mb would work

[ptkato]

Fixed with https://github.com/jappeace/rentals/commit/7e6ca185cc1d0a514b316224f9347b09e24b77c5.