fix(imagepicker): consolidate API / Fix typings

[jcassidyav]

The IOS and Android APIs have diverged with each other, the .d.ts and the docs, this is an attempt to bring them all back into sync.

Changes:

• authorize() now returns a Promise<AuthorizationResult> for both android and IOS, where the authorized property indicates success, and the details property holds the returned value from the call to @nativescript-community/perms, previously IOS threw an error on , and android returned the raw response from @nativescript-community/perms which came in two different forms depending on android version.

• In the returned result from present() each result[i].thumbnail is now an ImageSource, this was previously a BitMap for android / ImageSource for IOS.

• result[i].duration is now typed correctly as a number, previously typed as a string, but was always set with a number.

• Uses @nativescript-community/perms in IOS.

[NathanWalker]

Really nice thank you @jcassidyav