Add Token Standard v2 references in the docs: API reference, overview, etc.

[hrischuk-da]

Token Standard v2 is live on DevNet. It should be referenced in the docs in the various locations where Token Standard v1 is.

[isegall-da]

@OriolMunoz-da @meiersi-da have we not produced docs for token std v2? Or just haven't ported them to cf-docs?

[OriolMunoz-da]

@isegall-da
@meiersi-da said he would get to canton-network/splice#4582 after his vacation via DM on Slack. If we need it urgently, I can take a stab at it tomorrow.