"read-only" DB mode, and optional index creation

[GorgiAstro]

Hi,

First of all thanks for the awesome mongo backend.

Is it possible to have a mode where the MongoDB is not written? For safety reasons I am using stac_fastapi_mongo with a read-only MongoDB user.
The only issue I have is the calls create_collection_index() and create_item_index() which I had to comment out, otherwise it causes an error because of my read-only MongoDB user. I don't need to create these MongoDB indexes because my software which feeds data into the MongoDB already takes care of it, so it would be nice to make this optional.

[jonhealy1]

Hi. Nice to hear from you. Would you be able to create a pr for this issue?

[GorgiAstro]

Yes I can. Is it okay to enable/disable the two calls create_collection_index() and create_item_index() using an environment variable (with the default value being the current behaviour, i.e. performing these two calls)?

[jonhealy1]

Hi @GorgiAstro sounds good! Thank you

[GorgiAstro]

I opened a PR: #31

[GorgiAstro]

Closed by #31