chore(macros/HTTPSidebar): Reorg HTTP sidebar after doc reshuffle, de…

…lete 'Basics of HTTP' (#11753)

* chore(http): Reorg HTTP sidebar after doc reshuffle, delete 'Basics of HTTP'

* chore(http): improvements following reviewer feedback

* test(macros/HTTPSidebar): update test expectation

* chore(macros/HTTPSidebar): remove 'null, text[...]' from smartLinks

* chore(macros/HTTPSidebar): remove 'null, text[...]' from smartLinks

* chore(macros/HTTPSidebar): tests following sidebars changes

* chore(http): Changes following reviewer feedback, removed unused l10n keys

---------

Co-authored-by: Claas Augner <caugner@mozilla.com>