Fix send IRSend for Pioneer devices (#6100)

[s-hadinger]

Description:

After spending the ween-end to remote debug the issue from #6100 and with the help of @Oprtyo

It appears that Pioneer timings are 5% shorter than NEC. If you're lucky, some devices will tolerate the difference, but some will not. This fixes aligns timing to actual Pioneer IR. For example, the NEC preamble is 9ms + 4.5ms, whereas the Pioneer timing is 8.5ms and 4.25ms. Frequency is also 40KHz instead of 38KHz.

I also introduced an easier way to add IR codes above SHARP (14). Pioneer code is 50 in IRRemoteESP8266, which would require very long strings.

The feature depends on the #define USE_IR_SEND_PIONEER toggle that I enabled by default. @arendst you decide whether you accept to keep it enabled (there are lots of Pioneer devices out there) or if it requires custom compile.

Note: I will make a PR for IRRemoteESP8266 to make it hopefully official.

Code increase: 240 bytes.

Related issue (if applicable): fixes #6100

Checklist:

• The pull request is done against the latest dev branch
• Only relevant files were touched
• Only one feature/fix was added per PR.
• The code change is tested and works on core 2.3.0, 2.4.2 and 2.5.2
• The code change pass travis tests. Your PR cannot be merged unless tests pass
• I accept the CLA.