[ZIP-233] Network Sustainability Mechanism: Burning

[giddie]

This mostly consists of the addition of a burn_amount transaction field, introduced in the ZFuture network upgrade. Enabling cfg(zcash_unstable = "zfuture") meant that a lot of TZE code was unnecessarily enabled, so we switched some of those sections to zcash_unstable = "tze" as well as introducing zcash_unstable = "nsm" to keep things separate. The zfuture cfg is now used just to enable the ZFuture network upgrade.

The code for the generated test vectors is available in this PR.

[codecov]

Codecov Report

Attention: Patch coverage is 41.66667% with 35 lines in your changes missing coverage. Please review.

Project coverage is 61.56%. Comparing base (81d8ad4) to head (0ac99f7).
Report is 64 commits behind head on main.

Files with missing lines	Patch %	Lines
zcash_primitives/src/transaction/mod.rs	42.85%	16 Missing ⚠️
zcash_primitives/src/transaction/builder.rs	20.00%	8 Missing ⚠️
zcash_primitives/src/transaction/txid.rs	57.14%	6 Missing ⚠️
zcash_client_sqlite/src/wallet.rs	0.00%	4 Missing ⚠️
devtools/src/bin/inspect/transaction.rs	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1567      +/-   ##
==========================================
- Coverage   61.62%   61.56%   -0.07%     
==========================================
  Files         148      148              
  Lines       18825    18873      +48     
==========================================
+ Hits        11601    11619      +18     
- Misses       7224     7254      +30     

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