Avoid using the reserved characters from RFC3986 in fields that are intended to form part of a URL (e.g. 'next_key'), or provide them already escaped.

[akarabashov]

We encountered an error during pagination due to special characters ('+' and '=') in the request URL.

https://on.dcl.csa-iot.org/dcl/model/models?pagination.key=AAARaC8AAAP+Lw==

These characters cause issues because they are reserved in RFC 3986. To prevent future errors, we need to modify DCL. It should either provide fields that can be used as URL parts without RFC 3986 characters or ensure that these characters are already properly escaped.