Chore: Renamed the Ledger Table to Account

Chore: Renamed the Ledger Model to Account
Chore: Renamed LedgerType to AccountType
Chore: Renamed all properties of Account table to lowercase with underscores

Feature: Starred Accounts and their entries do not delete during a rebase.
Info: Starred Vouchers still delete. They can be starred, but have no effect.

overlord/src/app/account/account-detail/account-detail.component.html

@@ -2,6 +2,9 @@
   <mat-card fxFlex>
     <mat-card-title-group>
       <mat-card-title>Account</mat-card-title>
+      <mat-icon matSuffix (click)="item.isStarred = !item.isStarred" class="pointer" [class.gold]="item.isStarred">
+        {{ item.isStarred ? 'star' : 'star_border' }}
+      </mat-icon>
     </mat-card-title-group>
     <mat-card-content>
       <form [formGroup]="form" fxLayout="column">