Update example policies because of changes for VC/VP proof functions

Closes #1

See merge request gaia-x/data-infrastructure-federation-services/tsa/policies!5

Update multi get header policy.

See merge request gaia-x/data-infrastructure-federation-services/tsa/policies!4

Signed-off-by: michev <georgi.michev@vereign.com>

Add get multi header policy.

See merge request gaia-x/data-infrastructure-federation-services/tsa/policies!3

Needed for testing make-header-value-a-string-in-rego.
Amend getHeader policy to follow the canonical format.

Signed-off-by: michev <georgi.michev@vereign.com>

Update get header policy.

See merge request gaia-x/data-infrastructure-federation-services/tsa/policies!2

The header should be with uppercase letters.

Signed-off-by: m1chev <veselinov.michev@gmail.com>

Add example policy for using headers in rego runtime

See merge request gaia-x/data-infrastructure-federation-services/tsa/policies!1

Migrate vereign to gaiax gitlab

See merge request gaiax/tsa-migrate/policies!1