Rename AblyRealtime to Ably

[ricardopereira]

• Tests
• Example project
• Push new pod

[ricardopereira]

target 'AblyClientApp' do
  pod 'Ably'
end

Tested the CocoaPod 'Ably' with Swift and Objective-C.

Import like

• Swift:

import Ably

• Objective-C

#import <Ably/Ably.h>

[ricardopereira]

⚠️ Create a new release from tag 0.8.6 after this has been merged.

[mattheworiordan]

Tasks:

• Merge in all other PRs before this release so 0.8 is complete, ideally with Reauth but we can do that after
• Create a new release from tag 0.8.7 after this has been merged.
• Update all references in documentation
• Update README
• Update CHANGELOG with important notice about the change.
• Include update in our next product update
• Deprecate old Pod so that it points to the new one (Cocoapods supports deprecation in favour of a new one)

[mattheworiordan]

@tcard I may need your help with this on Monday

[mattheworiordan]

@ricardopereira it does not look like all the tasks is this PR are going to be done, so please can you create a new issue now with those tasks so that we get those bits done?

[ricardopereira]

@mattheworiordan Ok, I will.