Add support for better client version details

[zivkovicmilos]

Description

This PR resolves a pending issue that doesn't return proper chain information on the client version.

It removes the base GET endpoint to the JSON-RPC layer, as it's not by the standard, nor should it be supported.
Users should use the web3_clientVersion endpoint instead, that is outlined in the specification.

Changes include

• Bugfix (non-breaking change that solves an issue)
• Hotfix (change that solves an urgent issue, and requires immediate attention)
• New feature (non-breaking change that adds functionality)
• Breaking change (change that is not backwards-compatible and/or changes current functionality)

Checklist

• I have assigned this PR to myself
• I have added at least 1 reviewer
• I have added the relevant labels
• I have updated the official documentation
• I have added sufficient documentation in code

Testing

• I have tested this code with the official test suite
• I have tested this code manually

Additional comments

Fix EDGE-709

[ZeljkoBenovic]

Overall looks good.
We should just consider if we're totally removing GET endpoint

[codecov]

Codecov Report

Merging #672 (2ca4a03) into develop (66897d8) will decrease coverage by 0.13%.
The diff coverage is 71.42%.

❗ Current head 2ca4a03 differs from pull request most recent head bc72aaa. Consider uploading reports for the commit bc72aaa to get more accurate results

@@             Coverage Diff             @@
##           develop     #672      +/-   ##
===========================================
- Coverage    52.70%   52.56%   -0.14%     
===========================================
  Files          130      130              
  Lines        17146    17111      -35     
===========================================
- Hits          9037     8995      -42     
- Misses        7461     7470       +9     
+ Partials       648      646       -2     

Impacted Files	Coverage Δ
jsonrpc/jsonrpc.go	25.53% <57.57%> (+7.29%)	⬆️
jsonrpc/dispatcher.go	55.00% <80.64%> (+1.17%)	⬆️
jsonrpc/web3_endpoint.go	80.00% <100.00%> (+10.00%)	⬆️
txpool/lookup_map.go	88.46% <0.00%> (-11.54%)	⬇️
blockchain/subscription.go	72.00% <0.00%> (-10.50%)	⬇️
blockchain/blockchain.go	51.62% <0.00%> (-1.63%)	⬇️
blockchain/testing.go	59.29% <0.00%> (-1.00%)	⬇️
types/receipt.go	11.57% <0.00%> (-0.25%)	⬇️
jsonrpc/filter_manager.go	76.96% <0.00%> (-0.21%)	⬇️
txpool/queue.go	80.46% <0.00%> (-0.16%)	⬇️
... and 13 more

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[0xAleksaOpacic]

LGTM, thank you for exelent tests coverage 🚀