apache/incubator-pegasus#1575

After all encryption related patches been cherry-picked from
[tikv](https://github.com/tikv/rocksdb/commits/6.29.tikv) and
merged, now we will improve the encrytion, including:
- Fix action job `build-linux-encrypted_env-no_compression-no_openssl`
  to build binaries without openssl and compression libs correctly.
- Fix action job `build-linux-encrypted_env-openssl` to export the
  `ENCRYPTED_ENV` enviroment variable correctly.
- Don not skip tests which are skipped by TiKV.
- Refactor `AESCTRCipherStream` and `AESEncryptionProvider` to support
  manage file key by the file itself, according to the design docs in
[Data at rest
encryption](apache/incubator-pegasus#1575).
- Remove all KeyManager related codes.
- Replace KeyManager tests by AES encryption tests.
- Refactor encryption/encryption_test.cc and add more tests.
- Make it possible to construct AESEncryptionProvider object via
  `EncryptionProvider::CreateFromString()` by registering a
  factory in "encryption" library.
  It's possible to construct an object by URI: `AES`, `AES://test` or
  `AES:<instance_key>,<EncryptionMethod>`.
- `ldb` tool support to parse `--fs_uri` flags as the URI mentioned
above.
- Add tests to create AESEncryptionProvider object in
  `CreateEncryptedEnvTest.CreateEncryptedFileSystem`
- `db_bench` support to run benchmark with encryption enabled, by adding
new flags for `db_bench`, they are `encryption_method` and
`encryption_instance_key`.
- Move code from the exported header directory (i.e.
include/rocksdb/encryption.h)
to rocksdb internal (i.e. encryption/encryption.h), do not expose them
to users.
- Code format.

Review hint: #17 shows all the
code changes
from the base branch (i.e. `pegasus-kv:v8.3.2-pegasus`), you can review
it together to
make sure the request branch `acelyc111:pk_enc_new` doesn't have vice
effect on the base.

Manual test:
```
// Generate some data.
./db_bench --encryption_method=AES128CTR --encryption_instance_key=test_instance_key  --num=10000

// Dump WAL OK
./tools/ldb --fs_uri="provider=AES; id=EncryptedFileSystem" dump_wal --walfile=/tmp/rocksdbtest-1000/dbbench/000004.log
./tools/ldb --fs_uri="provider=AES://test; id=EncryptedFileSystem" dump_wal --walfile=/tmp/rocksdbtest-1000/dbbench/000004.log
./tools/ldb --fs_uri="provider=AES:test_instance_key,AES128CTR; id=EncryptedFileSystem" dump_wal --walfile=/tmp/rocksdbtest-1000/dbbench/000004.log

// Dump WAL failed. Pass bad provider parameters to --fs_uri, e.g.
./tools/ldb --fs_uri="provider=AES1:test_instance_key,1AES128CTR; id=EncryptedFileSystem" dump_wal --walfile=/tmp/rocksdbtest-1000/dbbench/000004.log
./tools/ldb --fs_uri="provider=AES:bad_test_instance_key,AES128CTR; id=EncryptedFileSystem" dump_wal --walfile=/tmp/rocksdbtest-1000/dbbench/000004.log
./tools/ldb --fs_uri="provider=AES:test_instance_key,AES192CTR; id=EncryptedFileSystem" dump_wal --walfile=/tmp/rocksdbtest-1000/dbbench/000004.log

// The same to other ldb tools.

```