Enable "Seller accepts custom orders" per Gig

[miiila]

As the title says.

I was editing a gig I had paused since a long while and noticed that it would be useful to be able to toggle that button separately for each gig.

Of course, there’d need to be some notice on the gig for buyers to know that they can order the gig in question only “as is”.

It could save both sides time/frustration when sellers generally do accept custom orders (can be contacted) but would like to also offer gigs without that option (for example, if they offer 3 gig tiers for transcription, up to 5/10/15 minutes, they might want customers with 8 minutes to directly order the “up to 10 minutes” gig and to not ask for a custom offer for 8 minutes).