Add HC tutorial placeholder

[jyellick]

The existing HC tutorial document exists in the legacy repo. Rather than adding a banner or other notice of deprecation (which is rather implicit by being in the legacy repo), this PR creates a placeholder file in the new repo and marks it as a WIP.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 28.21%. Comparing base (c339901) to head (f9e0bbe).
Report is 4 commits behind head on develop.

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Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #161      +/-   ##
===========================================
+ Coverage    18.95%   28.21%   +9.26%     
===========================================
  Files          158      168      +10     
  Lines         6226     7294    +1068     
  Branches      1311     1311              
===========================================
+ Hits          1180     2058     +878     
- Misses        4971     5130     +159     
- Partials        75      106      +31     

Flag	Coverage Δ
cannon-go-tests	82.20% <ø> (?)
chain-mon-tests	27.14% <ø> (ø)
common-ts-tests	26.72% <ø> (ø)
contracts-bedrock-tests	0.62% <ø> (ø)
contracts-ts-tests	12.25% <ø> (ø)
core-utils-tests	44.03% <ø> (ø)
sdk-next-tests	38.59% <ø> (ø)
sdk-tests	38.59% <ø> (ø)

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see 10 files with indirect coverage changes