IF: Use string for variant format of fc::dynamic_bitset

[heifner]

Original format in the recorded IBC demo:

"qc_extension": {
  "qc": {
     "block_num": 135,
     "qc": {
       "_strong_votes": [
         15
       ],
       "_sig": "SIG_BLS_xxx"
    }
  }
}

Format before this PR:

  "qc_extension": {
    "qc": {
      "block_num": 135,
      "qc": {
        "_strong_votes": {
          "size": 5,
          "bits": [
            15
          ]
        },
        "_sig": "SIG_BLS_xxx"
      }
    }
  },

Format in this PR:
A character in the string is '1' if the corresponding bit is set, and '0' if it is not. Character position i in the string corresponds to bit position b.size() - 1 - i.

  "qc_extension": {
    "qc": {
      "block_num": 135,
      "qc": {
        "_strong_votes": "01111",
        "_sig": "SIG_BLS_xxx"
      }
    }
  },

Also rename some reflected types so their JSON name does not have a _ prefix.

[greg7mdp]

Format before this PR:

why is "size": 5. I thought there were 3 finalizers?
why "bits": [ 31 ]. I would have expected the same 7 as before

Format in this PR:

7 should translate to "_strong_votes": "111",

[heifner]

Format before this PR:

why is "size": 5. I thought there were 3 finalizers? why "bits": [ 31 ]. I would have expected the same 7 as before

Format in this PR:

7 should translate to "_strong_votes": "111",

It is not the same number of finalizers in the examples.

[greg7mdp]

It is not the same number of finalizers in the examples.

The examples illustrating the changes by this PR should use the same data for clarity I think.

[heifner]

It is not the same number of finalizers in the examples.

The examples illustrating the changes by this PR should use the same data for clarity I think.

Updated the PR description to use the same example.

Implementation has significantly changed.

[ericpassmore]

Note:start
group: IF
category: INTERNALS
summary: Update representation of variant formate for fc::dynamic_bitset to make votes more readable.
Note:end