feat: add in-transit XCM msgs in blocks endpoint (#1412)
* feat: add in-transit XCM msgs in blocks endpoint * change responses structure & namings - added `IHorizontalMessageInRelayChain` interface - renamed `IHorizontalMessage` to `IHorizontalMessageInParachain`. - renamed `paraId` to `originParaId` in `IHorizontalMessageInParachain` and `IUpwardMessage` interface. - corrected `ISanitizedParachainInherentData` - updated tests * changed response structure of upward msgs (multiple upward from same originPara) - upward msgs response to be aligned with horizontal msgs response structure - added Tarik's suggestions * updated docs * docs fix in schemas based on Iker's finding * Iker's grammar correction Co-authored-by:IkerAlus <[email protected]> * rebuilt docs --------- Co-authored-by: