package/ola: reintroduce package at version 0.10.8

The ola package (Open Lighting Architecture) version 0.10.2 was
removed in commit e692e1f2 due to an
incompatibility with the protobuf version 3.2.0 present in Buildroot
at that time.

ola was fixed to support newer protobuf version in:
https://github.com/OpenLightingProject/ola/pull/1630

This commit reintroduce this package at version 0.10.8.
For changelogs since its removal at 0.10.2, see:
- https://github.com/OpenLightingProject/ola/releases/tag/0.10.3
- https://github.com/OpenLightingProject/ola/releases/tag/0.10.4
- https://github.com/OpenLightingProject/ola/releases/tag/0.10.5
- https://github.com/OpenLightingProject/ola/releases/tag/0.10.6
- https://github.com/OpenLightingProject/ola/releases/tag/0.10.7
- https://github.com/OpenLightingProject/ola/releases/tag/0.10.8



This commit is based on the previously removed ola package, with the
following rework:
- Remove the dependency on BR2_HOST_GCC_AT_LEAST_4_5 as host gcc is
  now guaranteed to be at least 4.8.
- Update target gcc dependency to >= 4.8 to reflect protobuf
  requirement.
- Remove the BR2_PACKAGE_OLA_SLP option, which was removed in
  ola 0.9.4.
- Change the "DMX4Linux" plugin option name to "Open DMX" to better
  reflect the ola option (DMX4Linux is a legacy plugin for 2.6
  Kernels).
- Update Python support to version 3.x only
- Remove patches, as they are no longer needed
- Add options for ola plugins: ftdidmx, gpio, karate,
  openpixelcontrol, renard, spi, uartdmx, usbdmx
- Reorder options alphabetically
- Update project URL
- Add license hashes

Signed-off-by: Julien Olivain <ju.o@free.fr>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>