feat: skip downloading files if they already exist

[pradel]

Description

During the seed process, something might go wrong when you insert things in the DB so you want to retry the process. Currently you will always redownload the required files even tho they are on your system. To speed up things we could download these files only if they don't exist. Wdyt of this approach @wileyj ?

Type of Change

• Other

Does this introduce a breaking change?

I don't think so

Are documentation updates required?

No

[CLAassistant]

All committers have signed the CLA.

[wileyj]

rather than not download the file, i think it would be better to check the checksum of local vs remote before downloading. edit: typed "delete" when i meant "download"