docs(site): left-align the Docker Agent logo in the header

The header's inner row was wrapped in \`max-width: 1600px; margin: 0 auto\`,
so on wide monitors the logo drifted toward the page center instead
of sitting at the leftmost gutter. docs.docker.com keeps its product
logo flush left at the page padding edge \u2014 do the same. The header
uses \`padding: 0 24px\` to space content from the viewport edge, which
is enough; the inner element no longer needs its own constraint.\n\nReported by review of #2793.

Author: dgageot

docs/css/style.css

@@ -180,8 +180,6 @@ body {
   align-items: center;
   justify-content: space-between;
   width: 100%;
-  max-width: 1600px;
-  margin: 0 auto;
 }
 
 .header-logo {