Details:
Subcommands and Subcommand groups not yet implemented, they will require for some parts of the code to be re-done. More attributes can and should be implemented, such as [Required] and [Choice(... , ...)].
Breakdown:
* Rectified line endings to LF, as per the settings of the project.
* Added a new command to SlashCommandService and SlashCommandServiceHelper to register the found commands to discord.
* Implemented CommandRegistrationOptions that can be used to configure the behaviour on registration - what to do with old commands, and with commands that already exist with the same name. A default version exists and can be accessed with CommandRegistrationOptions.Default
* Modified the sample program to reflect the changes made to the SlashCommandService and to also register a new command that tests all 6 types of CommandOptions (except subcommand and subcommand group)
* At the moment all commands are registered in my test guild, because the update for global commands is not instant. See SlashCommandServiceHelper.RegisterCommands(...) or line 221.
* Modified SlashCommandInfo to parse arguments given from Interaction, unde in ExecuteAsync, and added method BuilDcommand that returns SlashCommandCreationProperties - which can be registered to Discord.
* Renamed in the sample project PingCommand.cs to DevModule.cs
* Added custom attribute Description for the command method's parameters.
* Implemented SlashParameterInfo - and extension of the OptionBuilder that implements a method name Parse - takes DataOptions and gives out a cast object to be passed to the command Delegate. Planning on doing more with it.
* Moved SlashCommandBuilder.cs to the same directory structure
* Moved SlashCommandModule.cs and ISlashCommandModule.cs to its own folder.

* Implemented Pending property

* Implemented changes

* feature: Add MessageFlags and AllowedMentions to Modify

* Change exception message

Added SocketApplicationCommands, Added method in SocketGuild to fetch that guilds ApplicationCommands.

Tested all rest routes and fixed them accordingly.

Did more testing and I think its ready to go

New Rest entities: RestApplicationCommand,RestGlobalCommand, RestGuildCommand, RestApplicationCommandOption, RestApplicationCommandChoice, RestApplicationCommandType.

Added public methods to the RestClient to fetch/create/edit interactions.

* fixes #1495

* keep obsolete properties and return types for compatibility

* missing properties for SocketInvite

* Restore xml docs and change obsolete message

Co-authored-by: Paulo <pnmanjos@hotmail.com>

Signed-off-by: Still Hsu <dev@stillu.cc>

Signed-off-by: Still Hsu <5843208+Still34@users.noreply.github.com>

Signed-off-by: Still Hsu <5843208+Still34@users.noreply.github.com>

Signed-off-by: Still Hsu <5843208+Still34@users.noreply.github.com>

Signed-off-by: Still Hsu <5843208+Still34@users.noreply.github.com>

* Fix: HasAllMembers is false if a user left

* Fix: Correct boolean logic

* Update SocketGuild.cs

* Fix returns value docs

Signed-off-by: Still Hsu <dev@stillu.cc>

Co-authored-by: Still Hsu <dev@stillu.cc>

The inherited summary incorrectly stated that all users who _see_ the channel are returned when in reality only the ones _connected_ are.

* Add inline replies

* Missed a few things

* Change xml docs, IUserMessage, and other changes

* Missed one when changing

* Fix referencedMessage author

* Send presence on identify

* Change CurrentUser presence