Rename default filtering to avoid misuse

[nuke-web3]

Many users have been confused in the context of about Everything vs. Nothing - what does this mean in the filtering context? Do you allow Everything or block Everything? This was a security issue amended in the template:

        // Was `Everything`, created security issues on XCM filters! 
    type XcmReserveTransferFilter = Nothing;

To resolve this ambiguity, I propose we go back to the terms AllowAll and DenyAll that are much more concretely understood.

[leonardocustodio]

@NukeManDan there you go, hope it helps.

Regards,

[deepink-mas]

How about fixing by a reformulation of Filter to Allow:

type XcmReserveTransferAllow = Nothing;