Implement SVCB and HTTPS RRs (#32)

* Add MessageDecoder#get_list

This method repeats yielding until all the data upto the current limit
is consumed, and then returns an Array containig the block results.

* Implement SVCB and HTTPS RRs [RFC 9460]

> This patch implements SVCB and HTTPS resource record types defined in
> [RFC 9460].
> 
> The RR types are now supported by many server implementations including
> BIND, unbound, PowerDNS, and Knot DNS. Major browsers such as Chrome,
> Edge, and Safari have started to query HTTPS records, with the records
> gradually adopted by websites. Also, SVCB is actually deployed in the
> public DNS resolvers such as Cloudflare DNS and Google Public DNS for
> [DDR].
> 
> With such wide adoption, we have plenty of real-world use cases, and
> it is unlikely the wire format will change further in an incompatible
> way. It is time to implement them in the client libraries!
> 
> # Rationale for proposed API
> 
> ## `Resolv::DNS::Resource::IN::ServiceBinding`
> 
> This is an abstract class for SVCB-compatible RR types.
> SVCB-compatible RR types, as defined in the Draft, shares the wire
> format and the semantics of their RDATA fields with SVCB to allow
> implementations to share the processing of these RR types. So we do
> so.
> 
> The interface of this class is straightforward: It has three
> attributes `priority`, `target`, and `params`, which correspond the
> RDATA fields SvcPriority, TargetName, and SvcParams, resp.
> 
> SVCB RR type is defined specifically within IN class. Thus, this
> class is placed in the `Resolv::DNS::Resource::IN` namespace.
> 
> ## `Resolv::DNS::Resource::IN::SVCB`, `Resolv::DNS::Resource::IN::HTTPS`
> 
> Just inherits ServiceBinding class.
> 
> ## `Resolv::DNS::SvcParam`
> 
> This class represents a pair of a SvcParamKey and a SvcParamValue.
> Aligned with the design of `Resolv::DNS::Resource`, each SvcParamKey
> has its own subclass of `Resolv::DNS::SvcParam`.
> 
> ## `Resolv::DNS::SvcParam::Generic`
> 
> This is an abstract class representing a SvcParamKey that is unknown
> to this library. `Generic.create(key)` dynamically defines its
> subclass for specific `key`. E.g., `Generic.create(667)` will define
> `Generic::Key667`.
> 
> This class holds SvcParamValue in its wire format.
> 
> SvcParam with an unknown SvcParamKey will be decoded as a subclass of
> this class. Also, users of this library can generate a non-supported
> SvcParam if they know its wire format.
> 
> ## `Resolv::DNS::SvcParams`
> 
> This is conceptually a set of `SvcParam`s, whose elements have the
> unique SvcParamKeys. It behaves like a set, and for convenience
> provides indexing by SvcParamKey.
> 
> - `#initialize(params)` takes an Enumerable of `SvcParam`s as the
>   initial content. If it contains `SvcParam`s with the duplicate key,
>   the one that appears last takes precedence.
> - `#[](key)` fetches the `SvcParam` with the given key. The key can be
>   specified by its name (e.g., `:alpn`) or number (e.g., `1`).
> - `#add(param)` adds a `SvcParam` to the set. If the set already has a
>   `SvcParam` with the same key, it will be replaced.
> - `#delete(key)` deletes a `SvcParam` by its key and returns it. The key
>   can be specified by its name or number.

* Update comments referring to draft-ietf-dnsop-svcb-https-12

Published as RFC 9460. https://datatracker.ietf.org/doc/rfc9460/

[draft-ietf-dnsop-svcb-https-12]: https://datatracker.ietf.org/doc/draft-ietf-dnsop-svcb-https/12/
[RFC 9460]: https://datatracker.ietf.org/doc/rfc9460/
[DDR]: https://datatracker.ietf.org/doc/draft-ietf-add-ddr/