RFR: bot: add profile handler [v2]

[Erik Helin]

> Hi all,
> 
> please review this patch that adds a "profiling handler" typically listening on the `/profile` path. The profile handler will create a JFR recording that is sent as the reply to the HTTP request. The handler needs to configure a max duration (in seconds) for the recording and and a path to the `.jfc` configuration file. I made sure that only recording is allowed at a time to prevent too many requests to slow down the system too much.
> 
> Testing:
> - [x] Tested locally on Linux x64 with various bots and configurations
> 
> Thanks,
> Erik

Erik Helin has updated the pull request incrementally with two additional commits since the last revision:

 - Fixup
 - Require auth header

-------------

Changes:
  - all: https://git.openjdk.java.net/skara/pull/1164/files
  - new: https://git.openjdk.java.net/skara/pull/1164/files/bd09ee70..2fabd94e

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=skara&pr=1164&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=skara&pr=1164&range=00-01

  Stats: 26 lines in 1 file changed: 24 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/skara/pull/1164.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/1164/head:pull/1164

PR: https://git.openjdk.java.net/skara/pull/1164