Feat: Add slash command to generate application form for various community roles

[christolis]

Closes #1024.

Screenshots

Configuration changes

Property	Description	Type	Default
applicationForm.applicationChannelPattern	Where submitted applications end up.	String	"applications-log"

TODO

• [x] Add a 5 minute cooldown per member for sending applications to prevent spam (feel free to recommend alternatives).
  • This could be done by having a HashMap<Member, OffsetDateTime> where the key is the Member who sent an application and the value is the date and time that they sent it. There should be a condition every time a Member attempts to send any application which utilizes the aforementioned HashMap to prevent spam.
• [x] Add JavaDocs for every method where it's necessary.
• [x] ~~Switch to EntitySelectInteractionEvent for the dropdown menu.~~ (EDIT: Impossible since this would forcibly include all existing roles)
• [x] Move selectable roles from the config to the command parameters in a similar fashion with previous commands.
  • This eliminates emoji/description metadata as well that was previously defined in the configuration file.

[Suleman70]

Can i be assigned to this?

[christolis]

Marked PR as draft since there needs to be some rework on certain things which will be specified in the TODO.