feature(rpc): add real data to getinfo method

[oxarbitrage]

Motivation

Implement the getinfo RPC method with the fields used by lightwalletd. Close #3142 if merged.

Solution

I had a hard time trying to pass the app version into the method. This approach is with lazy_static. I am open to change this if i find something that works and it is better.

This PR does not have a specific test, i am unsure if the tests we will use will be acceptance or something else for each method. If they are acceptance then the test for this call should be added after #3641 as it is very similar to what we have now.

The code in this pull was tested manually:

$ curl -X POST -H "Content-Type: application/json" -d '{"jsonrpc": "2.0", "method": "getinfo", "params": [], "id":123 }' 127.0.0.1:8832 | jq
{
  "jsonrpc": "2.0",
  "result": {
    "build": "1.0.0-beta.5+22.g45caa63",
    "subversion": "/Zebra:1.0.0-beta.5/"
  },
  "id": 123
}
$ 

The docs for the method are in a discussion at #3638. Open to change the format.

Review

Probably @teor2345 will be the best option if they have time so i can have some feedback for my morning.

Reviewer Checklist

• Lazy static implementation is acceptable.
• If so, check the code as a whole.

[teor2345]

This PR does not have a specific test, i am unsure if the tests we will use will be acceptance or something else for each method.

@oxarbitrage this seems like it might be a decision for the whole team. Did you want to put it on the engineering sync agenda for tomorrow?

[codecov]

Codecov Report

Merging #3660 (3c6c7c7) into main (729535c) will decrease coverage by 0.08%.
The diff coverage is 33.33%.

@@            Coverage Diff             @@
##             main    #3660      +/-   ##
==========================================
- Coverage   80.06%   79.98%   -0.09%     
==========================================
  Files         284      288       +4     
  Lines       32740    32755      +15     
==========================================
- Hits        26214    26198      -16     
- Misses       6526     6557      +31     

[teor2345]

I haven't tried this myself, but I think it might simplify things.

[teor2345]

Looks good, let's check what tests we need with the team before we merge.

[oxarbitrage]

Lets add some basic test here before we merge. This will also define the test structure for all the methods.

[teor2345]

Looks great, thanks!