SKALED-1431 debug_getFutureTransactions call

[dimalit]

Waiting for merge from latest develop

Test sequence:

1. Add balance for your account to skaled's config.
2. Run skaled with --enable-debug-behavior-apis
3. Send transaction with too big nonce.
4. Send curl -X POST --data '{"id":4,"jsonrpc":"2.0","method":"debug_getFutureTransactions","params":[]}' <URL>
5. See your transaction.
6. Repeat the same without --enable-debug-behavior-apis, METHOD_NOT_FOUND error should be returned.

[github-actions]

SUGGESTIONS BEFORE MERGE:

1. Build custom container here: https://github.com/skalenetwork/skaled/actions?query=workflow%3A%22Custom+Docker+and+Binary%22
2. Test it here: https://github.com/skalenetwork/skale-ci-integration_tests/actions?query=workflow%3A%22Skaled+Nightly+Tests%22
3. Edit VERSION file appropriately to your changes!
   See https://skalelabs.atlassian.net/wiki/spaces/SKALE/pages/2444951553/Branching+instructions

[codecov]

Codecov Report

Merging #1754 (430e686) into v3.18.0 (f7c560a) will increase coverage by 0.02%.
The diff coverage is 7.14%.

Additional details and impacted files

@@             Coverage Diff             @@
##           v3.18.0    #1754      +/-   ##
===========================================
+ Coverage    45.50%   45.53%   +0.02%     
===========================================
  Files          356      356              
  Lines        51720    51735      +15     
===========================================
+ Hits         23537    23557      +20     
+ Misses       28183    28178       -5