feat: add getParsedConfirmedTransaction API

[jstarry]

Problem

• Need API for getting parsed confirmed transactions from RPC

Summary of Changes

• Add getParsedConfirmedTransaction method to Connection

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Halfway through typing up all of the token instructions, I decided to add them directly to the explorer..

• Typing is super time intensive given our Flow / old superstruct / type def files setup
• It probably makes more sense for these types to live in @solana/spl-token
• I don't know of any immediate need for them inside web3

Fixes #

[codecov]

Codecov Report

Merging #11412 into master will decrease coverage by 7.8%.
The diff coverage is 13.3%.

@@            Coverage Diff             @@
##           master   #11412      +/-   ##
==========================================
- Coverage    81.9%    74.0%    -7.9%     
==========================================
  Files         320       29     -291     
  Lines       75012     1309   -73703     
  Branches        0      154     +154     
==========================================
- Hits        61449      969   -60480     
+ Misses      13563      304   -13259     
- Partials        0       36      +36