[actions] ideas for faster github actions / OF compile

[dimitre]

It is already great most of the actions are running under 10 minutes
but some minor changes can shave off some seconds or minutes

• Using always make -j2 on github actions
• install and cache apt packages in linux actions
• makefile no boost #7845
• comment out boost from install scripts, install_dependencies.sh using one line apt get #7838
• Make - using automatic number of cores #7849

Removing boost paths

it was used only for c++ filesystem compatibility but OF is now c++14 up
we can left the library as it is in the case somebody needs, or even upgrade in apothecary to be compatible with a more complete filesystem.

• Removing Boost paths from OF XCode project #7837
• remove boost from openframeworksLib.vcxproj

Removing Poco paths

Poco is not needed anymore by the core or projectGenerator. we can move any flag if needed to ofxPoco

• remove POCO from some places (config.msys2.default.mk, openFrameworksDebug.props, openframeworksLib.vcxproj, openFrameworksRelease.props)

Using CCACHE

• [actions] msys2 ccache #7850
• ccache on rpi
• ccache on emscripten ?
• adapt already used previously ccache to this one with persistent cache
  https://github.com/marketplace/actions/ccache-for-gh-actions