fix(nginx): add option to easy manage HEADERS (make it possible to set HSTS)

[wrenix]

Description of the change

Benefits

Possible drawbacks

Applicable issues

• fixes #

Additional information

Checklist

• [ ] I have read the CONTRIBUTING.md doc.
• [x] DCO has been signed off on the commit.
• [x] Chart version bumped in Chart.yaml according to semver.
• [ ] (optional) Parameters are documented in the README.md

[wrenix]

i move all headers to values.yaml -> docs are coming

[wrenix]

ping @jessebot

[jessebot]

@wrenix looks good to me, feel free to merge :)