Support custom TLS certificate for S3-compatible backend

[aldy505]

objectstore/objectstore-server/src/config.rs

Lines 54 to 57 in f4858c0

	S3Compatible {
	endpoint: String,
	bucket: String,
	},

The Dockerfile is distroless, that means users need to rebuild the image in order to use a custom TLS certificate. It would be nice if we can add a path to the custom TLS certificate, and make reqwest read it as reqwest::tls::Certificate, and then pass it onto reqwest::Client. https://docs.rs/reqwest/latest/reqwest/tls/struct.Certificate.html