feat: add validator id and verification to echo and ready messages

[gruberb]

Description

Introducing ValidatorId to verify that ECHO | READY message come from a valid validator. We also add a signature to EACH | READY messages. Therefore the double_echo has to be aware of the validator private key (secret).

Fixes TP-677 and TP-678

Additions and Changes

• Adding signing_key to the TceConfig
• Adding signature and validator_id to DoubleEchoCommand and ProtocolEvents::Echo and ProtocolEvents::Ready.

PR Checklist:

• 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
• I have added or updated tests that comprehensively prove my change is effective or that my feature works

[codecov]

Codecov Report

Patch coverage: 79.39% and project coverage change: +0.77% 🎉

Comparison is base (2b7517c) 57.64% compared to head (ad9ce40) 58.41%.
Report is 2 commits behind head on main.

❗ Current head ad9ce40 differs from pull request most recent head 0c48074. Consider uploading reports for the commit 0c48074 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #298      +/-   ##
==========================================
+ Coverage   57.64%   58.41%   +0.77%     
==========================================
  Files         228      230       +2     
  Lines       11807    11998     +191     
==========================================
+ Hits         6806     7009     +203     
+ Misses       5001     4989      -12     

Files Changed	Coverage Δ
crates/topos-crypto/src/lib.rs	50.00% <ø> (ø)
crates/topos-sequencer-subnet-client/src/lib.rs	0.00% <ø> (ø)
...pos-sequencer-subnet-client/src/subnet_contract.rs	0.00% <ø> (ø)
crates/topos-tce-api/tests/runtime.rs	92.74% <ø> (ø)
crates/topos-tce-broadcast/src/sampler/mod.rs	87.50% <ø> (+46.32%)	⬆️
crates/topos-tce-gatekeeper/src/client.rs	88.23% <ø> (ø)
crates/topos-tce/src/config.rs	0.00% <ø> (ø)
crates/topos-tce/src/lib.rs	0.00% <0.00%> (ø)
crates/topos-test-sdk/src/tce/mod.rs	86.39% <ø> (ø)
crates/topos/src/components/node/services.rs	20.20% <0.00%> (-0.42%)	⬇️
... and 17 more

... and 11 files with indirect coverage changes

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[dvdplm]

🎉