When the Portal ("suit" application) is started up on the lsst-lsp-int instance of the LSST Science Platform, the initial TAP screen comes up pointed at the lsst-lsp-stable.ncsa.illinois.edu TAP service. Both the -stable and -int services are configured into the TAP service menu, which used to work semi-accidentally, but now that authorization is fully enabled, only the matching TAP service will be accessible (-stable Portal must talk to -stable TAP, -int Portal must talk to -int TAP).

This "instance matching" has been in the design all along.

The TAP service list is currently statically configured in https://github.com/lsst/suit/blob/master/src/suit/js/SUIT.js

Can we change this code to get the LSST TAP service URL by extracting the base URL from the URL of the currently displayed page? (Technically, by extracting everything before "/portal".)

We need this change not only to get `-int` working properly by default, but also to get this working on cloud-based LSP deployments. Whatever the Portal URL is, let's say "https://lsst.codes/lsp/portal", the TAP service URL needs to be "https://lsst.codes/lsp/api/tap".