[docs] fees consolidated

[nickfrosty]

Problem

There are multiple docs and bits of information scattered about the various fees on solana. They are also outdated and/or duplicated in various areas.

Summary of Changes

• consolidated the fee docs into one single doc
• updated the content itself too
• updated the links and redirects for these pages

[nickfrosty]

lol @mikemaccana I said I was about half way done with this

[nickfrosty]

Merged per conversation at off-site @jacobcreech