Update implementation for cleaner mutations

[TejasQ]

Why

• We were not resetting error states on refetch (!)
• We decided to rename host to base
• I was incorrectly using setState (thanks, @Xiot!)
• lint-staged was incorrectly configured and did not work on precommit.
• <Get lazy and then calling post inside its body seemed like a workaround.
• Errors were being caught and handled inside the library when instead how they're handled should be up to consumers.
• index.tsx exported a whole bunch of other things, while containing the GET definition.

Changes

• Better error handling, now passing response (The response is never passed #6)
• Renamed host prop to base (Add CodeSandbox examples and link in README.md #2)
• Removed useless console.log
• Cleaned up precommit hook (it actually works now)
• <Mutate component that handles HTTP verbs that are not GET.
• Errors are thrown and left for users to handle in a catch block.
• Cleaner file structure.

This will result in a new major version because of API breakage.

[Xiot]

This deprecation warning doesn't make sense on the base prop.