SEC-2177: Striping off all leading schemes

Striping off all leading schemes in the DefaultRedirectStrategy, so it will be less vulnerable to open redirect phishing attacks.
This change is desired for our product, so either we'll copy source code and adjust ContextRelativeRedirectStrategy to our needs, or we’ll wait and use modified SpringSecurity’s component (which is obviously more preferable solution).
More details can be found at [SEC-2177](https://jira.spring.io/browse/SEC-2177) JIRA issue.

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