Turn on Anonymous login to lower the barrier for session feedback

[MrCsabaToth]

I didn't realize until Valley DevFest 2019 that someone cannot add a session feedback

Expected Behavior

Someone would be able to add a session feedback even if not logged in. We assume the participants won't troll the website. If there's trolling that will probably be able to be filtered anyway.

Current Behavior

If someone just visits the website the feedback controls are not visible since the user is not logged in.

Possible Solution

Enable Firebase's Anonymous login feature. This way the user can even assemble "My Schedule" and also can add session feedback without a full login.

Steps to Reproduce

1. 2. 3. 4.

Context (Environment)

Any (given no login was done by the user)

Detailed Description

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Possible Implementation

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[MrCsabaToth]

This ticket also:

• Introduces support for multiple providers besides Google: Facebook, Twitter, Github
• Handles complex cases of account linking and unlinking besides enabling Anonymous login

[MrCsabaToth]

Unfortunately #17 is discovered as a bug.