ApPredict for use with Chaste 2021.1

This version of ApPredict is compatible with Chaste 2021.1 which can be downloaded here.

What's Changed

• Switching to Model factory method by @MauriceHendrix in #10
  • Users now supply the model which should be used with --model this can be:
    • a path to a CellML file (relative or absolute) for runtime CellML conversion, OR
    • a CellML model name (filename without the .cellml) for using any CellML included at compile-time, OR
    • an old hardcoded integer choice (deprecated).
• forced hund_rudy_2004 not to use the analytic jacobian. by @MauriceHendrix in #5
• Switching off analytic jacobian (generated by codegen) by default by @MauriceHendrix in #7

Setting up automated github testing

• Adding ApPredict GitHub Actions workflow on self-hosted Ubuntu 20.04 runners by @kwabenantim in #11
• #3099 Add failed test notifications for Slack by @kwabenantim in #12
• #3099 Fix force-failed test suite by @kwabenantim in #13

Full Changelog: v2019.1...v2021.1