chore: migrate the simpleserialize.com from ssz monorepo

[nazarhussain]

Used the following steps to migrate the git history.

# Clone the source repo
git clone git@github.com:ChainSafe/ssz.git ssz-temp
cd ssz-temp

# Create a new branch for the extraction
git checkout -b extract-simpleserialize

# Installed git tool, git builtin `filter-branch` recommended this tool
brew install git-filter-repo

# Rewrite the repo to only contain packages/simpleserialize.com
git filter-repo --path packages/simpleserialize.com --path-rename packages/simpleserialize.com/:

# Add the target repo as a remote
git remote add target https://github.com/ChainSafe/simpleserialize.com.git

# Fetch the target repo
git fetch target

# Create a new branch based on the target's main branch
git checkout -b feature/merge-from-ssz target/main

# Merge the extracted history and resolve all the conflicts manually
git merge --allow-unrelated-histories extract-simpleserialize

# Push the new branch to the target repo
git push target feature/merge-from-ssz

NOTE:
The only caveat is that we were releasing this static site every time we release the packages. But that has no effect because static site has dependencies to older versions of the ssz packages.