Updating Readme with build instructions for ViroReact

Step - by - Step instructions for building Android and iOS instructions.

Removing pod install from build scripts

The problem we were having so far with build iOS bridge through pipelines
was that each time we did pod install, React scheme would vanish from Xcode
and then the build script would crap with "React scheme not found".
We don't update our Pods very often (probably once in 6 months). So instead of
dealing with running manual builds just for iOS build, we'll instead install pods manually, when we update them.


Former-commit-id: ad51ccc3f4d37ee343d1234495e937270088c695

Bump viroreact version to 2.11.0

Former-commit-id: 26725a651ddfed1ce3bf8657ad9eed75f1b53264

Fixing initial crash with autofocus

If the scene started with autofocus turned on from the begining,
we were crashing since ARCore wouldnt be initialized then.


Former-commit-id: cc1a6aa7ac9393a896766d49f0cf9aaf28c9b6da

Updating fastlane script to build and upload iOS release test in sing…

…le lane

Former-commit-id: b4dbadd9310629a56ee02595a4f2a5ac2763abc9

Unmute build slack messages

Former-commit-id: a14272fb2e96d8df013c20eb1e5481290a585806

viro react v2.7.3.

Adding building bridge for simulator to fastlane

Former-commit-id: 07a459c645dae9b23501ed8f791ff63148cbb3fd

Bump version number to 2.6.1

Former-commit-id: 28a8e4b39f67c4f82635c7d7952a97d0ceeed77f