Add DomainStrategy to JSONv5 outbound

[57a4c324e742]

Added domainStrategy field for outbound in JSONv5 configuration file. This feature was introduced in #2334 and is only available in the JSONv4 configuration format.

This pull request:

• Repair and close DomainStrategy Setting Has no Effect in Freedom Outbound while Using jsonv5 Format #2448
• Restore the ability to use internal DNS resolution with "freedom" outbound. Related commit 40d75fa.

Credits:

• @Vigilans for the feature implementation
• @YVjXuB for report the problem

Usage:

{
	"outbounds": [
		{
			"protocol": "freedom",
			"tag": "freedom",
			"domainStrategy": "USE_IP"
			// USE_IP, Use_IP, UseIP, USE_IPV4, Use_IPv4, UseIPv4, USE_IPV6, Use_IPv6, UseIPv6
		}
	]
}

I was not able to create single commit by using web editor, please consider using squash when merging this pull request.

[Vigilans]

#2334 Adds DomainStrategy for outbound's SenderSettings, which coexists with freedom's Config in JsonV4. Now both is absent in JsonV5.

Do you think in this PR we should add both config for JsonV5 for compatibility, or just add to outbound's SenderSettings to advocate the usage of newer generic one?

---

Edit: 40d75fa actually lacks a whole bunch of freedom outbound config in JSONv4:

v4:

v2ray-core/proxy/freedom/config.proto

Lines 16 to 27 in 2ac0188

	message Config {
	enum DomainStrategy {
	AS_IS = 0;
	USE_IP = 1;
	USE_IP4 = 2;
	USE_IP6 = 3;
	}
	DomainStrategy domain_strategy = 1;
	uint32 timeout = 2 [deprecated = true];
	DestinationOverride destination_override = 3;
	uint32 user_level = 4;
	}

v5:

v2ray-core/proxy/freedom/config.proto

Lines 29 to 32 in 2ac0188

	message SimplifiedConfig {
	option (v2ray.core.common.protoext.message_opt).type = "outbound";
	option (v2ray.core.common.protoext.message_opt).short_name = "freedom";
	}

So bringing freedom's config back may be done in a separated PR.

[57a4c324e742]

@Vigilans The new configuration format already brought us lot of breaking change, so I'm fine with the new unified one without the compatible design.

[AkinoKaede]

I think it's better to throw an exception when domainStrategy is set to an incorrect value to alert the user.

[xiaokangwang]

I think this merge request can be merged in principle, however, some modification will be needed to make sure there is only one recognized value for each options and throws explicit errors otherwise.

[xiaokangwang]

I will merge and make modification myself.