sharex-server

Allow more types other than images to be uploaded and viewed such as videos and text, and allow unsupported types to be downloaded, but with a warning.

After trying to move the project to use tokio, unfortunately I had an error thread 'actix-rt:worker:0' panicked at 'there is no reactor running, must be called from the context of a Tokio 1.x runtime', /usr/local/cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.12.0/src/runtime/blocking/pool.rs:84:33
Not sure what caused it, since it uses the latest tokio.