Fix local initialization script

[yzang2019]

Describe your changes and provide context

Problem:
Initialize_local.sh is broken on Mac because sed command is not working on latest MacOS:

sed -i 's/mode = "full"/mode = "validator"/g' $HOME/.sei/config/config.toml
sed: 1: "/Users/yzang/.sei/confi ...": unterminated transform source string

Fix:
sed is little bit different on Mac compared to Linux GNU, we need to change the command to this
sed -i'.bak' -e 's/something/else'g' filepath

Testing performed to validate your change

Tested on Mac and Ubuntu

[github-actions]

Package	Line Rate	Complexity	Health
github.com/sei-protocol/sei-chain/aclmapping/bank	100%	0	✔
github.com/sei-protocol/sei-chain/aclmapping/dex	97%	0	✔
github.com/sei-protocol/sei-chain/aclmapping/oracle	100%	0	✔
github.com/sei-protocol/sei-chain/aclmapping/staking	82%	0	✔
github.com/sei-protocol/sei-chain/aclmapping/tokenfactory	96%	0	✔
github.com/sei-protocol/sei-chain/aclmapping/utils	0%	0	❌
github.com/sei-protocol/sei-chain/aclmapping/wasm	83%	0	✔
github.com/sei-protocol/sei-chain/app	52%	0	➖
github.com/sei-protocol/sei-chain/app/antedecorators	89%	0	✔
github.com/sei-protocol/sei-chain/oracle/price-feeder/config	85%	0	✔
github.com/sei-protocol/sei-chain/oracle/price-feeder/oracle	73%	0	➖
github.com/sei-protocol/sei-chain/oracle/price-feeder/oracle/provider	49%	0	❌
github.com/sei-protocol/sei-chain/oracle/price-feeder/router/v1	45%	0	❌
github.com/sei-protocol/sei-chain/store/whitelist/cachemulti	100%	0	✔
github.com/sei-protocol/sei-chain/store/whitelist/kv	100%	0	✔
github.com/sei-protocol/sei-chain/store/whitelist/multi	100%	0	✔
github.com/sei-protocol/sei-chain/utils	46%	0	❌
github.com/sei-protocol/sei-chain/utils/datastructures	90%	0	✔
github.com/sei-protocol/sei-chain/x/dex	59%	0	➖
github.com/sei-protocol/sei-chain/x/dex/cache	86%	0	✔
github.com/sei-protocol/sei-chain/x/dex/client/cli/query	23%	0	❌
github.com/sei-protocol/sei-chain/x/dex/contract	52%	0	➖
github.com/sei-protocol/sei-chain/x/dex/exchange	89%	0	✔
github.com/sei-protocol/sei-chain/x/dex/keeper	61%	0	➖
github.com/sei-protocol/sei-chain/x/dex/keeper/abci	30%	0	❌
github.com/sei-protocol/sei-chain/x/dex/keeper/msgserver	78%	0	✔
github.com/sei-protocol/sei-chain/x/dex/keeper/query	82%	0	✔
github.com/sei-protocol/sei-chain/x/dex/migrations	85%	0	✔
github.com/sei-protocol/sei-chain/x/dex/types	1%	0	❌
github.com/sei-protocol/sei-chain/x/dex/types/utils	100%	0	✔
github.com/sei-protocol/sei-chain/x/dex/types/wasm	83%	0	✔
github.com/sei-protocol/sei-chain/x/epoch	11%	0	❌
github.com/sei-protocol/sei-chain/x/epoch/keeper	66%	0	➖
github.com/sei-protocol/sei-chain/x/epoch/types	2%	0	❌
github.com/sei-protocol/sei-chain/x/mint	0%	0	❌
github.com/sei-protocol/sei-chain/x/mint/keeper	75%	0	➖
github.com/sei-protocol/sei-chain/x/mint/simulation	95%	0	✔
github.com/sei-protocol/sei-chain/x/mint/types	2%	0	❌
github.com/sei-protocol/sei-chain/x/nitro/client/cli	45%	0	❌
github.com/sei-protocol/sei-chain/x/nitro/keeper	80%	0	✔
github.com/sei-protocol/sei-chain/x/nitro/replay	63%	0	➖
github.com/sei-protocol/sei-chain/x/oracle	63%	0	➖
github.com/sei-protocol/sei-chain/x/oracle/keeper	82%	0	✔
github.com/sei-protocol/sei-chain/x/oracle/simulation	18%	0	❌
github.com/sei-protocol/sei-chain/x/oracle/types	3%	0	❌
github.com/sei-protocol/sei-chain/x/tokenfactory/keeper	85%	0	✔
github.com/sei-protocol/sei-chain/x/tokenfactory/types	2%	0	❌
Summary	15% (4919 / 33806)	0	❌

[yzang2019]

@philipsu522 I updated with the change to remove password requirement, and added some instructions for how to submit a proposal. Please take another look, thanks!