Add error or more direct warning to deprecated "query" extension

[robbibt]

The most recent version of Explorer no longer supports the "query" syntax (in favour of STAC's recommend "filter" syntax).

Although this is mentioned in a new warning from PySTAC, this is not very descriptive and doesn't explain that users should use "filter" instead:

This change risks users running into "silent failure" issues where they think that "query" is being applied when it is not (and getting back unfiltered data accidentally).

To avoid this, we should add either a hard error (forcing users to adapt their code to use "filter" instead), or a more descrptive warning message advising users to swap to "filter".