FBT: Don't lint JS packages

[Willy-JL]

What's new

• support for excluding folders in linter with ! prefix
• exclude js packages dir as they have js naming convention (using dashes) so fbt would always complain

Verification

• ./fbt format does not complain of applications/system/js_app/packages/fz-sdk and applications/system/js_app/packages/create-fz-app

Checklist (For Reviewer)

• PR has description of feature/bug or link to Confluence/Jira task
• Description contains actions to verify feature/bugfix
• I've built this code, uploaded it to the device and verified feature/bugfix

[skotopes]

To be honest ! symbol is quite problematic in terms of how shell handles it.
It will work here, since args passed directly to subprocess without shell involvement.