[interceptor/transformer] feat:support setFloat/setInt/setBool

[zhu733756]

Proposed Changes:

• [interceptor/transformer] feat:support setFloat/setInt/setBool, it is the same with set + strconv, but set the value once

Which issue(s) this PR fixes:

Fixes #621

Additional documentation:

interceptor: support setFloat/setInt/setBool

1. an older configuration is：
  - type: transformer
    name: setEmpty
    actions:
    - if: NOT exist(count)
      then:
        - action: set(count, 0)
        - action: strconv(count, float)
        - action: return()
      else:
        - action: return()

2. the newly configuration is: 
  - type: transformer
    name: setEmpty
    actions:
    - if: NOT exist(count)
      then:
        - action: setFloat(count, 0)
        - action: return()
      else:
        - action: return()

[zhu733756]

/cc @ethfoo