chore: simplify ca cert handling for app and inso

[jackkav]

The first request could be getting blocked by file writes, this process is avoided by using the CAINFO_BLOB feature of node-libcurl

• Moves ca cert loading outside of the request path to main app start and inso send-request.
• Inso now uses os.tmpdir() rather than stubbing electron to point at os.tmpdir()
• considering making all main/nodejs tmpdir calls use os.tmpdir() for consistency.
• NOTE Oauth2 flow still blocking a clear renderer seperation, so we can't remove the getTempDir() helper just yet as react component code paths are still hit by oauth2 re-request.
• blob support was added in feat: support curl_blob options JCMais/node-libcurl#300 looks like it should work 🚀 and allows us to eliminate two file writes!

Future work

• remove electron shim from inso abstraction.
• encourage oauth 2 re-request loop to respect architectural boundaries.
  • remove conditional window/electron and window/require hacks

Closes INS-1511

[johnwchadwick]

LGTM, nice. I honestly forgot that we already got the node-libcurl side of things done :)

[dimitropoulos]

@jackkav sorry I didn't catch this in time, but maybe get rid of the extra space before esr in a future PR some time if you remember it.