chore: Align ExternalSecret name pattern(#213)

[alezander86]

Description

Align External Secret name pattern, renamed external secrets files and resource name for consistency.

Fixes (#213)

Type of change

• Enhancement (non-breaking change which improves an existing feature or documentation)

Checklist:

• I have performed a self-review of my code
• I have commented on my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Pull Request contains one commit. I squash my commits.