optimise yarahunter

[ibreakthecloud]

• Using string.Join on million of record is really slow. Using Map here were reads and writes are in o(1)
• using fmt writes the error log to stdout, that then goes to json. which we don't want.

// todo

• size of output(result) json can grow depending on stringsMatch, need fix for that
• size of map will increase the in-mem usage, need to fix this

[ibreakthecloud]

This changes were benchmarked by @ramanan-ravi @ibreakthecloud @gnmahanth @noboruma @akumars1 on different setups

Username	Now	Before
@ramanan-ravi	9m30s	> 30m
@ibreakthecloud	30m	~1 day
@noboruma	< 30m	> 30m
@akumars1	14m	infinite
@gnmahanth	5m	> 30m

cc: @shyam-dev