/api/search/{domain}: Add IDN compatibility

[DL6ER]

What does this implement/fix?

Lowercase domains passed to GET /api/search/{domain} and convert them to punycode (if applicable), e.g., GET /api/search/äBC.cOm (mind the Umlaut ä) will now actually trigger a search for xn--bc-uia.com

Related issue or feature (if applicable): N/A

Pull request in docs with documentation (if applicable): N/A

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Checklist:

• The code change is tested and works locally.
• I based my code and PRs against the repositories developmental branch.
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[yubiuser]

Works locally, but not remotely

nanopi@nanopi:~$ curl -s 127.0.0.1/api/search/äBC.com?debug=true | jq .search.debug.punycode
"xn--bc-uia.com"


chrko@ThinkPad-X230:~$ curl -s 10.0.1.24/api/search/äBC.com?debug=true
Error 400: Bad Request


chrko@ThinkPad-X230:~$ curl 10.0.1.24/api/search/abc.com?debug=true
{
	"search":	{
		"domains":	[],
		"gravity":	[],
		"results":	{

[DL6ER]

@yubiuser Should now be fixed. From my point of view, this is a bug in the CivetWeb server. I opened a PR with our proposed fix upstream: civetweb/civetweb#1209

[yubiuser]

Works as expected

chrko@ThinkPad-X230:~$ curl -s 10.0.1.24/api/search/äBC.com?debug=true
{
	"search":	{
		"domains":	[],
		"gravity":	[],
		"results":	{
			"domains":	{
				"exact":	0,
				"regex":	0
			},

[DL6ER]

civetweb/civetweb#1209 has been merged upstream without changes.