Adding accessibility identifiers to PFLogInView and PFSignUpView

[huguesbr]

Adding accessibility identifiers for easier UI Automation Testing.

[nlutsenko]

Whee! This is great! Didn't know someone actually cares about ui testing our components. 😁
Nitpicky review is coming, so bare with me through the process, but I would love to merge it when it's done.

[nlutsenko]

Nit: Per our style - could you remove the space between * and const, as the star should only be space separated on the left.

[nlutsenko]

Ok, that's about it as far as I can see right now.
The nits apply to the entire PR, meaning that there are more places with the same issue, but I left it out to avoid pollution. Let me know if any of them don't quite make sense or if there is anything I can help you with.

[huguesbr]

@nlutsenko done! thx for the thorough review

[facebook-github-bot]

@huguesbr updated the pull request.

[huguesbr]

@nlutsenko anything else, it should be PR ready..!

[nlutsenko]

Nit: Add line break before line 41 per overall code style.

[nlutsenko]

Few missing/extra line breaks and will merge it in.

[facebook-github-bot]

@huguesbr updated the pull request.

[huguesbr]

@nlutsenko all done.. wish there was a good linter for objc-c... thx

[nlutsenko]

We are using a clang-format file, but it can't quite catch these things...
So for the time being I work part-time as a linter. 😁

[nlutsenko]

Last piece - could you squash all commits into a single one? I will merge it straight after.

[huguesbr]

@nlutsenko done

[nlutsenko]

Whee!

[huguesbr]

@nlutsenko thx for playing linter...