Fix curlicue-setup filename quoting, use -X POST style
Update options/variables/if/usage style
Support long arg (--request) for curl HTTP method
Make the jq filter a normal getopts option
Replace url_encode function with script that calls curl
Encode params, don't DWIM their placement or resource names

Names should look like they look in the official API documentation. And
there should be one obviously correct way to specify params, now that we
can encode them properly.
If we only use single-character delimiters, this is simpler

The RFC says whitespace in the Authorization header is optional. The
temporary-delimiter approach here was fragile anyway, and only worked by
dumb luck ('&' as the RHS, unescaped, replaced the match with itself).
Use jq's string interpolation syntax for example
Alphabetize and improve formatting of options help