Implement TryFrom<String> for PrincipalData

[friedger]

Summary of Changes

This PR implements conversion from string to principal data that is used by the sbtc cli to enable deposits to stacks contracts.

Fixes #299

Testing

Risks

This enables users to deposit sbtc to a contract without any checks whether the contract exists or can handle recieved sbtc tokens.

How were these changes tested?

• unit test added
• manual test in devenv (with non-existing contract)

What future testing should occur?

Integration test

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[friedger]

While there is a risk to loose sbtc by sending to a contract, this possibility might inspire developers at the hackathon.

[codecov]

Codecov Report

Merging #300 (74ea7df) into main (eac5a87) will increase coverage by 0.59%.
Report is 4 commits behind head on main.
The diff coverage is 86.56%.

@@            Coverage Diff             @@
##             main     #300      +/-   ##
==========================================
+ Coverage   43.12%   43.71%   +0.59%     
==========================================
  Files          45       45              
  Lines        5359     5433      +74     
  Branches       47       47              
==========================================
+ Hits         2311     2375      +64     
- Misses       3047     3057      +10     
  Partials        1        1              

Flag	Coverage Δ
unittests	76.61% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
stacks-core/src/lib.rs	34.21% <ø> (+2.63%)	⬆️
sbtc-cli/src/commands/deposit.rs	0.00% <0.00%> (ø)
stacks-core/src/crypto/wif.rs	61.97% <0.00%> (ø)
stacks-core/src/utils.rs	95.71% <92.06%> (-1.57%)	⬇️

... and 5 files with indirect coverage changes

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[stjepangolemac]

Generally looks good but let's make it a bit more idiomatic and then merge.