refactor: remove compatibility mode

Since the switch to the `mat-` prefix, the compatibility mode is no longer necessary. These changes remove anything that was left.

BREAKING CHANGE:
The `MATERIAL_COMPATIBILITY_MODE`, `CompatibilityModule`, `NoConflictStyleCompatibilityMode`, `MatPrefixRejector`, `MdPrefixRejector` symbols have been removed.

Author: crisbeto

.github/CODEOWNERS

@@ -36,7 +36,6 @@ src/lib/core/option/**             @kara @crisbeto
 src/lib/core/rxjs/**               @jelbourn
 src/lib/core/ripple/**             @devversion
 src/lib/core/a11y/**               @jelbourn @devversion
-src/lib/core/compatibility/**      @jelbourn
 src/lib/core/overlay/**            @jelbourn @crisbeto
 src/lib/core/overlay/scroll/**     @andrewseguin @crisbeto
 src/lib/core/platform/**           @jelbourn @devversion

guides/compatibility-mode.md

@@ -8,7 +8,6 @@
 
 import {NgModule, InjectionToken, Optional, Inject, isDevMode} from '@angular/core';
 import {BidiModule} from '@angular/cdk/bidi';
-import {CompatibilityModule} from '../compatibility/compatibility';
 
 
 /** Injection token that configures whether the Material sanity checks are enabled. */
@@ -17,13 +16,13 @@ export const MATERIAL_SANITY_CHECKS = new InjectionToken<boolean>('mat-sanity-ch
 
 /**
  * Module that captures anything that should be loaded and/or run for *all* Angular Material
- * components. This includes Bidi, compatibility mode, etc.
+ * components. This includes Bidi, etc.
  *
  * This module should be imported to each top-level component module (e.g., MatTabsModule).
  */
 @NgModule({
-  imports: [CompatibilityModule, BidiModule],
-  exports: [CompatibilityModule, BidiModule],
+  imports: [BidiModule],
+  exports: [BidiModule],
   providers: [{
     provide: MATERIAL_SANITY_CHECKS, useValue: true,
   }],

src/lib/core/common-behaviors/common-module.ts

@@ -8,7 +8,6 @@
 
 export * from './animation/animation';
 export * from './common-behaviors/index';
-export * from './compatibility/compatibility';
 export * from './datetime/index';
 export * from './error/error-options';
 export * from './gestures/gesture-annotations';