feat: release Astroport v4 with native xASTRO on Neutron

[epanchee]

This PR aims to bring new contracts and adjustments across the whole codebase to comply with new native xASTRO token. All these changes are required for proper Hub move to Neutron.

Related PRs:

• feat: release Astroport Governance v3 astroport-governance#109
• feat: release new features for the Hub move to Neutron astroport_ibc#37

Notable changes

• staking contract now supports only native xASTRO minted on Neutron. Balances tracking implemented via astroport-tokenfactory-tracker contract (see periphery/tokenfactory_tracker) which is set as bank hook upon tokenfactory token creation;
• Old cw20.ASTRO can be converted to new TF (token-factory) ASTRO version on any outpost inplace. You don't want to bridge old astro to Terra to do conversion there. astro_converter chain-agnostic contract serves this purpose. Note that this contract doesn't allow conversion in opposite direction i.e. TF ASTRO -> cw20.ASTRO.
• To ease integrations and to smoothen UX we've developed virtual pair which aims to hide conversion logic behind the scenes (see contracts/pair_astro_converter). You will be able to use Astroport UI to swap cw20.ASTRO -> TF ASTRO at 1:1 ratio via usual swap tool or using astroport router contract.
• Special migration endpoint in vesting contract (which serves as a "ASTRO bank" on each outpost) to convert old cw20.astro to tf astro on each outpost. After this migration ASTRO emissions will be turned into token factory form. Hence further reward claiming will be given in new token factory ASTRO;
• Removed unused and obsolete contracts such as cw20_ics20, pair_astro_xastro, native-coin-wrapper, shared_multisig, token (which was basically copy-pasted from official cosmwasm cw20), generator, xastro_outpost_token. Removed outdated TS deploy scripts.