Documentation improvements (#2069)

* docs: fix documentation in various places

All stores: resolveID returns a nullable Snowflake
GuildAuditLogs: ActionType also can be ALL
MessageEmbed: make files property show up in the docs
ClientApplication: resetSecret and resetToken return a promise
ClientManager: status is readonly
Guild: features is an array of strings and ban no longer accepts a number or string
Guild: ban method no longer accepts a string or number
GuildMember: ^
RichPresenceAssets: small and large Image are Snowflakes, also fixed parameter documentation for small and large image url method
WebhookMessageOptions: file property is no longer a thing

* docs: improve GuildAuditLogs documentation

Prefix types with AuditLog to avoid confusion
Document GuildAuditLogs' static Targets and Actions properties and add necessary typedefs
Use typdefs over primitives where possible.

* fix documentation for Guild#defaultRole

src/structures/Webhook.js

@@ -79,7 +79,6 @@ class Webhook {
    * (see [here](https://discordapp.com/developers/docs/resources/channel#embed-object) for more details)
    * @property {boolean} [disableEveryone=this.client.options.disableEveryone] Whether or not @everyone and @here
    * should be replaced with plain-text
-   * @property {FileOptions|BufferResolvable} [file] A file to send with the message
    * @property {FileOptions[]|string[]} [files] Files to send with the message
    * @property {string|boolean} [code] Language for optional codeblock formatting to apply
    * @property {boolean|SplitOptions} [split=false] Whether or not the message should be split into multiple messages if