chore: remove git restrictions with pre-git and add semantic validator for pr

[hanwencheng]

Description

1. remove any restrictions on commit
2. add semantic validator to add the following types in front of the PR as what we do before with commit. @goldsteinsveta

Additional Configurartions

Since I can not change the settings of the repo, to use it we still need to do followings administration with this repo:
Install Semantic Pull Request on Github, start here.

Another thing is that I suggest we only allow Squash Merging under merge button.

Trouble Shooting

If after this PR you still met the restrictions with commit, please delete git hook repository

$parity-signer    rm -rf  .git/hooks/

[Tbaut]

Another thing is that I suggest we only allow Squash Merging under merge button.

Not entirely sure why we would use the others, but since squash-merge is the default I don't really mind keeping the other options in case it can help. There's no overhead.

[Tbaut]

Thanks for that, I installed semantic-pull-requests on the repo :)