Release v0.0.3

Rework plugin to new structure.

Added nagios-interval syntax support
Added bats testing framework
- Added tests for current (old) behavior and syntax.
- Added tests for new behavior and syntax.
Autodetect vector / scalar query types based on query result.
Check intervals using jq instead of test -v
Support floats instead of integers all around.
Utilize epsilon instead of 1 for old syntax.
Added CI testing and release management.