Ubuntu Jammy support.

[mkalcok]

Dependency: This change to layer:beats-base has to be merge as well for proper Ubuntu 22.04 support (more info in the PR).

This change adds support for deployment of filebeats charm on Ubuntu 22.04 and adds charmcraft.yaml file for build compatibility with charmcraft.

Two main changes were needed:

• Drop dependency on charms.templating.jinja2 which depends on Tempita package that does not work on python3.10 (More info in PR linked above)
• Add clone3 syscall to list of allowed syscalls. Absence of this syscall caused an issues that are described in this Github Issue (It's from apm project, not filebeats but the problem and the solution are the same)

Resolves #94

[Pjack]

LGTM

[Pjack]

1. Please also check if there is any useful code in this PR provided by Alvaro before. I will drop his PR after merge this one.
2. How to link this issue to this PR?

[mkalcok]

I linked #94 issue and added Alvaro's changes to the README.md

[agileshaw]

Thanks for the PR. I've made a suggestion in the inline comment.

[agileshaw]

As we already supports filebeat 7, could you please check if this syscall is also needed for filebeat-7.yaml? You can test it by replacing the default value of install_sources config option with "deb https://artifacts.elastic.co/packages/7.x/apt stable main"

[mkalcok]

I wanted to mention this in the description but I forgot. Filebeat 7 has this problem fixed in 7.15.2 so I don't think we need to explicitly configure it.

[kwmonroe]

This LGTM, but i'm curious if you need jammy listed in the metadata.yaml:

https://github.com/juju-solutions/layer-filebeat/blob/master/metadata.yaml

I presume that charmcraft and the pack/push procedure means you don't, but wanted to double check just in case it was an oversight.

[agileshaw]

@kwmonroe Thanks for the review. The series in metadata.yaml is deprecated if using charmcraft. The best practice would be to replace the line with series: []. But since we are planning to refactoring the charm in near future, I think we can leave it as is right now and save the change in a new PR.