Move file caching logic to new FileCache service

Also: removes the -re ffmpeg option.
If this option is passed, ffmpeg won't write to fs-capacitor (and the cache file) as fast as possible.
In other words, the cache file won't finish writing until the entire stream has been played.

src/models/file-cache.ts

@@ -1,13 +1,13 @@
 import {Table, Column, PrimaryKey, Model} from 'sequelize-typescript';
 
 @Table
-export default class FileCache extends Model<FileCache> {
+export default class FileCache extends Model {
   @PrimaryKey
   @Column
   hash!: string;
 
   @Column
-  kbits!: number;
+  bytes!: number;
 
   @Column
   accessedAt!: Date;

src/models/key-value-cache.ts

@@ -2,7 +2,7 @@ import {Table, Column, PrimaryKey, Model} from 'sequelize-typescript';
 import sequelize from 'sequelize';
 
 @Table
-export default class KeyValueCache extends Model<KeyValueCache> {
+export default class KeyValueCache extends Model {
   @PrimaryKey
   @Column
   key!: string;

src/models/settings.ts

@@ -1,7 +1,7 @@
 import {Table, Column, PrimaryKey, Model, Default} from 'sequelize-typescript';
 
 @Table
-export default class Settings extends Model<Settings> {
+export default class Settings extends Model {
   @PrimaryKey
   @Column
   guildId!: string;

src/models/shortcut.ts

@@ -1,7 +1,7 @@
 import {Table, Column, PrimaryKey, Model, AutoIncrement, Index} from 'sequelize-typescript';
 
 @Table
-export default class Shortcut extends Model<Shortcut> {
+export default class Shortcut extends Model {
   @PrimaryKey
   @AutoIncrement
   @Column