[TM-281] [WIP] Propagating changes through codebase

Description

• Added CPairs CT CT ctor to CT.
• Set/Map/BigMap now operates with comparable T key.
• Only Tc {} and Each Comparable [l, r] => TPair l r are comparable.

Related issue(s)

https://issues.serokell.io/issue/TM-281

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• Tests (see short guidelines)

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    • Haddock
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