Fix README.me anchor to Download

RNFetchBlobFS.writeFile(): improve IO error handling

convert to new react native config format

Fix android Flag issue in android 9 and open file in Download directory in Android also

require cycle

Solve the conflict between FileProvider and other libraries

Androidx upgrade

fix cocoa pod 0.60.0 for rn-fetch-blob

Remove unused AsyncStorage import (Deprecated in RN 0.59)

This fixed the warning for "require cycle" on newer React-Versions

This reverts commit d69c72bb3f, reversing
changes made to c95ef1c199.

Add flow type definitions

update android build config for newer react-native versions

index.d.ts: Fix extends -> implements

Before:
```
node_modules/rn-fetch-blob/index.d.ts:147:43 - error TS2689: Cannot extend an interface 'EventTarget'. Did you mean 'implements'?

147 export declare class PolyfillBlob extends EventTarget {
                                              ~~~~~~~~~~~

error Command failed with exit code 1.
```

After:
```
✨  Done in 3.06s.
```

Add typescript type defenitions

Adding iOS background upload support

path sent to unlink is now checked for file prefix.

Fix 'Illegal Callback Invocation' Android exception

fix progress and uploadProgress not callback in iOS

Fixes a case where `callback` was called twice when something went wrong in the `cp` operation, leading to a `java.lang.RuntimeException: Illegal callback invocation from native module. This callback type only permits a single invocation from native code.`

This is the same fix [as seen in the original repo](https://github.com/wkh237/react-native-fetch-blob/pull/408).