Remove unused code. (#4689)

This PR removes some unused code, specifically:

* A patch file that should have been removed in #4553.
* The `EncryptionKeyValidation` class that is unused since #1197.
* Setting CMake policies to NEW that are already set by
`cmake_minimum_required(VERSION 3.21)`

---
TYPE: NO_HISTORY

Author: teo-tsirpanis

cmake/common.cmake

@@ -91,13 +91,3 @@ endif()
 include_directories(${CMAKE_SOURCE_DIR})
 cmake_path(SET TILEDB_SOURCE_ROOT NORMALIZE ${CMAKE_SOURCE_DIR})
 cmake_path(APPEND TILEDB_SOURCE_ROOT "external/include" OUTPUT_VARIABLE TILEDB_EXTERNAL_INCLUDE)
-
-#
-# Policies
-#
-if (POLICY CMP0076)
-    # CMP0076 NEW instructs `target_sources` to convert relative paths to absolute ones.
-    # At present this is only used for unit-test executables, not for the main
-    # library at the top level.
-    cmake_policy(SET CMP0076 NEW)
-endif()

ports/aws-sdk-cpp/fix-awsmigrationhub-build.patch

@@ -26,13 +26,6 @@
 # THE SOFTWARE.
 #
 
-############################################################
-# CMake policies
-############################################################
-
-# C++ library, allow the VISIBLITY_PRESET for each c++ target to work
-cmake_policy(SET CMP0063 NEW)
-
 ############################################################
 # Find packages needed for object libraries
 ############################################################
@@ -184,7 +177,6 @@ set(TILEDB_CORE_SOURCES
   ${TILEDB_CORE_INCLUDE_DIR}/tiledb/sm/consolidator/group_meta_consolidator.cc
   ${TILEDB_CORE_INCLUDE_DIR}/tiledb/sm/crypto/crypto.cc
   ${TILEDB_CORE_INCLUDE_DIR}/tiledb/sm/crypto/encryption_key.cc
-  ${TILEDB_CORE_INCLUDE_DIR}/tiledb/sm/crypto/encryption_key_validation.cc
   ${TILEDB_CORE_INCLUDE_DIR}/tiledb/sm/crypto/crypto_openssl.cc
   ${TILEDB_CORE_INCLUDE_DIR}/tiledb/sm/crypto/crypto_win32.cc
   ${TILEDB_CORE_INCLUDE_DIR}/tiledb/sm/curl/curl_init.cc