Add docs note about authenticated queries

[juanmcloaiza]

Addresses #3473

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 71.49%. Comparing base (83c5c73) to head (e5f62ad).
⚠️ Report is 21 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3477   +/-   ##
=======================================
  Coverage   71.49%   71.49%           
=======================================
  Files         234      234           
  Lines       20094    20094           
=======================================
  Hits        14366    14366           
  Misses       5728     5728           

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[keflavich]

Good clear addition to the instructions.

[bsipocz]

I see some docs build errors, I'll address them in review, rebase and then merge this.

Thank you @juanmcloaiza!

/Users/bsipocz/munka/devel/astroquery/docs/eso/eso.rst:107: WARNING: py:obj reference target not found: Eso.login() [ref.obj]
/Users/bsipocz/munka/devel/astroquery/docs/eso/eso.rst:107: WARNING: py:obj reference target not found: authenticated [ref.obj]
/Users/bsipocz/munka/devel/astroquery/docs/eso/eso.rst:123: WARNING: py:obj reference target not found: authenticated=False [ref.obj]

[bsipocz]

I'm adding one more commit and rebase this, otherwise the note box look great. Thanks!