Launchpad v2.1 - Vending Minter

In this update of vending minter contract includes the per wallet limit increase to 3% based on https://commonwealth.im/stargaze/discussion/8796-nft-market-listing-fee-maximum-mint-limit-per-wallet-changes.

### What's New
- Increase per wallet limit to 3%
- Add discount price support ported from v1



The source code is available at https://github.com/public-awesome/launchpad/releases/tag/v0.24.1

Compile instructions
```
docker run --rm -v "$(pwd)":/code \

--mount type=volume,source="$(basename "$(pwd)")_cache",target=/code/target
--mount type=volume,source=registry_cache,target=/usr/local/cargo/registry
cosmwasm/workspace-optimizer:v0.12.11

This results in the following SHA256 checksums:
5059e4db06caa21e6efe6844b7ec7c73efc6fbfe0e85a3bef0a396437671138e sg721_base.wasm
<br /># Verify on chain contract<br />
starsd q gov proposal $id --output json
| jq -r '.content.wasm_byte_code'
| base64 -d
| gzip -dc
| sha256sum
<br /><br /># Verify local contract<br />
sha256sum artifacts/sg721_base.wasm
```