Embedded support and CI fixes

What's Changed

• Tests by @fernandobatels in #21
• Setup continuous testing using GitHub Actions by @juarezr in #24
• Commented unused functions of the fbclient to fix tarpaulin build by @jairinhohw in #26
• Split into multiple crates by @jairinhohw in #27
• Allow using and testing multiple client implementations simultaneously by @jairinhohw in #28
• Embedded support by @fernandobatels in #29

Full Changelog: v0.4.0...v0.5.0