txn input validation (length, mismatch prevout)

[fuxingloh]

What kind of PR is this?:

/kind feature

What this PR does / why we need it:

Attempting to sign a txn without any vout will fail.
Attempting to sign a txn input P2WPKH will fail if provided prevout and elliptic pair are mismatched.

Which issue(s) does this PR fixes?:

Fixes #134

[github-actions]

size-limit report 📦

Path	Size	Loading time (3g)	Running time (snapdragon)	Total time
packages/jellyfish/dist/jellyfish.umd.js	18.88 KB (0%)	378 ms (0%)	173 ms (+3.27% 🔺)	550 ms

[netlify]

Deploy preview for jellyfish-defi ready!

Built with commit 000b84d

https://deploy-preview-190--jellyfish-defi.netlify.app

[codecov]

Codecov Report

Merging #190 (000b84d) into main (9619db1) will increase coverage by 0.12%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #190      +/-   ##
==========================================
+ Coverage   96.02%   96.15%   +0.12%     
==========================================
  Files          58       64       +6     
  Lines        1483     1559      +76     
  Branches      169      187      +18     
==========================================
+ Hits         1424     1499      +75     
- Misses         59       60       +1     

Impacted Files	Coverage Δ
packages/jellyfish-transaction/src/tx_signature.ts	97.75% <100.00%> (+0.31%)	⬆️
packages/testing/src/token.ts	100.00% <0.00%> (ø)
packages/testing/src/wallet.ts	100.00% <0.00%> (ø)
packages/testing/src/index.ts	100.00% <0.00%> (ø)
packages/testing/src/poolpair.ts	100.00% <0.00%> (ø)
packages/testing/src/rawtx.ts	92.30% <0.00%> (ø)
packages/testing/src/account.ts	100.00% <0.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update f6e67bf...000b84d. Read the comment docs.