File permission option for file consumer

[remyfrd]

I just taken an old PR: #26

I really need this.
We have many error with this chmod(..., 0777) like this in prod: chmod(): Operation not permitted

[codecov-io]

Codecov Report

Merging #122 into master will increase coverage by 0.33%.
The diff coverage is 100%.

@@             Coverage Diff              @@
##             master     #122      +/-   ##
============================================
+ Coverage     89.84%   90.18%   +0.33%     
- Complexity      124      125       +1     
============================================
  Files             8        8              
  Lines           384      387       +3     
============================================
+ Hits            345      349       +4     
+ Misses           39       38       -1

Impacted Files	Coverage Δ	Complexity Δ
lib/Segment/Consumer/File.php	97.14% <100%> (+3.39%)	16 <0> (+1)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update db4809a...98380a9. Read the comment docs.

[thibaudcharrier]

Same error for a Laravel app, the chmod raise an error, but segment reporting is working fine.
This chmod seems to be useless.

[nd4p90x]

LGTM, Thank you