[release-1.26] feat: add Out-Of-Date Documentation header for archive versions

[istio-testing]

Manual cherrypick required.

#16457 failed to apply on top of branch "release-1.26":

Applying: Added Deprecated Documentation Header
.git/rebase-apply/patch:17: trailing whitespace.
        <div class="archive-warning-banner" role="alert" 
.git/rebase-apply/patch:19: trailing whitespace.
        <p style="margin-bottom: 0;">⚠️ This documentation is for an older version (<strong>{{ $archiveVersion }}</strong>). 
.git/rebase-apply/patch:20: trailing whitespace.
            We recommend using the <a href="/latest{{ .RelPermalink | safeURL }}" 
warning: 3 lines add whitespace errors.
Using index info to reconstruct a base tree...
M	layouts/_default/baseof.html
Falling back to patching base and 3-way merge...
Auto-merging layouts/_default/baseof.html
CONFLICT (content): Merge conflict in layouts/_default/baseof.html
error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
hint: When you have resolved this problem, run "git am --continue".
hint: If you prefer to skip this patch, run "git am --skip" instead.
hint: To restore the original branch and stop patching, run "git am --abort".
hint: Disable this message with "git config advice.mergeConflict false"
Patch failed at 0001 Added Deprecated Documentation Header