views: disable caching on deposit edit

[jrcastro2]

• closes DOI registering issue CERNDocumentServer/cds-rdm#302

[slint]

nit: Flask responses have some fancy APIs, that allow you to do something like:

Suggested change

	response.headers["Cache-Control"] = "no-cache, no-store, must-revalidate"
	response.headers["Pragma"] = "no-cache"
	response.headers["Expires"] = "0"
	response.cache_control.no_cache = True
	response.cache_control.no_store = True
	response.cache_control.must_revalidate = True
	# Not 100% sure about these two
	response.pragma = "no-cache"
	response.expires = "0"