fix resolve of protolint.path if configured relative

[yrtimiD]

Fixes relative path usage which was resolved to the user folder (~), (very unexpected behavior)

This fix allows 3 cases for protolint.path config:

• empty or default protolint (used as-is)
• absolute path (used as-is)
• relative (resolved relatively to the first workspace folder)

Added settings caching. Added settings reload only if changed.