add the missing template for the login via socialaccount

[kimakan]

Currently, daiquiri uses the standard template from django-allauth, which doesn't use the styling of the website. For instance, see https://gaia.aip.de/accounts/google/login/?process=login.

This PR adds a simple login template for the redirection to the third party websites, which uses the styling of the website.

[coveralls]

Pull Request Test Coverage Report for Build 3873499323

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 65.837%

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Totals
Change from base Build 3845940112:	0.0%
Covered Lines:	4604
Relevant Lines:	6993

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💛 - Coveralls

[galkinAIP]

Thumbs up for merge.