Add the ability to import filters

[rddimon]

Just copied changes from the official PR mattrobenolt#86
And bump a version for building the internal package version

[amplify-bot]

Check Name	Conclusion	Summary	Output
Mend Security Check	neutral	Security Report	output
Mend License Check	neutral	License Report	output

[boonware]

@rddimon @mattrobenolt @kkozik-amplify This change was merged almost one year ago but the latest version from Pypi is still 0.8.2. Is this version 0.8.3 going to be released any time soon? The custom filters feature is a huge improvement and the very reason I decided to look for an alternative to jinja-cli.