switch to 'cross-fetch' instead of 'request'

[strmer15]

• Replaces request with cross-fetch, and isomorphic fetch library
  • The RequestOptions type is a mix of the browser and node-fetch options, so that server-side code can set things like the agent for keepalive, but it should have no effect in browser code
  • The lodash dependency was removed from the thrift-server-core library, because all it was used for was doing "deep merges" on the client, which weren't needed. Instead, a new function to merge together request options was added, with special logic for the Headers values (which can't utilize object spread).
  • The response.arrayBuffer() function is used to get an ArrayBuffer and convert the binary response into a Node Buffer, which is what the generated code expects to use when sending requests through the connection. We'll need to polyfill that with Webpack, but it should be just fine.
• Removed all uses of the url.parse and url.format deprecated functions and replaced them with the WHATWG URL API
• Fixed a number of tests and cleaned them up with the right response types

[anandkumarpatel]

Looks good! just some minor questions.

[markdoliner-doma]

Sorry for the slow review. Thanks for making these changes! It looks like there's a lot of good common-sense changes.

I'm not familiar with cross-fetch but I looked at it for a few minutes. Is it fair to say that it's a pretty small library, and it just proxies through to either a node implementation or a browser implementation depending on where it's running?

[strmer15]

Looks good! just some minor questions.

Thanks for reviewing!

[strmer15]

Sorry for the slow review. Thanks for making these changes! It looks like there's a lot of good common-sense changes.

Thanks for reviewing!

I'm not familiar with cross-fetch but I looked at it for a few minutes. Is it fair to say that it's a pretty small library, and it just proxies through to either a node implementation or a browser implementation depending on where it's running?

Yep, it just packages a browser implementation that uses the fetch library and then calls node-fetch when it's running on the server. See https://github.com/lquixada/cross-fetch#how-does-cross-fetch-work

[strmer15]

I'm going to merge so that I'm not blocked on the webpack 5 front anymore, but if anyone has any more comments or suggestions, I can address those in a separate PR. Thanks!