Add new parser: logfmt

[manuelluis]

No description provided.

[manuelluis]

The logfmt format is described in https://brandur.org/logfmt
a more formal description is in https://godoc.org/github.com/kr/logfmt

$ cat test.txt                      
key1=val1 key2=val2
key1=val1 key2 = val2
key1=val1 key2=val2 key3 key4= key5 key6=value6
key1=val1 key2=val2 key3="v \"a\" l u e"
key1=val1 key2=val2 key3="foo foo aaa lke = 65
key%^as$=val1 %asd.5$^ a b c d e

$ cat parser.conf                      
[PARSER]
    Name        logfmt
    Format      logfmt

$ ./fluent-bit -R parser.conf -i tail -p path=test.txt -p parser=logfmt -o stdout
Fluent-Bit v0.15.0
Copyright (C) Treasure Data

[2018/10/30 22:58:13] [ info] [engine] started (pid=30913)
[0] tail.0: [1540936693.000000000, {"key1"=>"val1", "key2"=>"val2"}]
[1] tail.0: [1540936693.000000000, {"key1"=>"val1", "key2"=>true, "val2"=>true}]
[2] tail.0: [1540936693.000000000, {"key1"=>"val1", "key2"=>"val2", "key3"=>true, "key4"=>true, "key5"=>true, "key6"=>"value6"}]
[3] tail.0: [1540936693.000000000, {"key1"=>"val1", "key2"=>"val2", "key3"=>"v \"a\" l u e"}]
[4] tail.0: [1540936693.000000000, {"key1"=>"val1", "key2"=>"val2", "key3"=>"foo foo aaa lke = 65"}]
[5] tail.0: [1540936693.000000000, {"key%^as$"=>"val1", "%asd.5$^"=>true, "a"=>true, "b"=>true, "c"=>true, "d"=>true, "e"=>true}]

Solves #562

[edsiper]

thanks @manuelluis !