Add fee info endpoint(s) (#57)

* Create initial skeleton of fee info endpoint

* Add endpoint for just submitting encoded extrinsic

* Clean up unused code

* Create initial skeleton of fee info endpoint

Add endpoint for just submitting encoded extrinsic

Clean up unused code

* Update path uri and descriptors in README.md

* Apply suggestions from code review

Co-authored-by: joe petrowski <[email protected]>

* Update path uri and descriptors in README.md

* Try and fix yarn.lock

* update to 1.17.0 beta 5 (#58)

* Change `fee-estimation` to post and update README.md


Fix small README typo

Fix uri in README curl example

* Update README.md

* Update README.md

Co-authored-by: joe petrowski <[email protected]>