[SVG] Memory optimzation of constructPath, Impl optimization of svg lengths

- Changed multiple string operations to one final operation for 'd' in constructPath. 
- Added units to all the svg lengths, as per https://jwatt.org/svg/authoring/#specifying-units
Don't join it here. Add utility function that will push items with spaces in between. But I would recommend to add space after each item at the end .join(' '). `M 1 2C 2 3ZM 1 0Z` does not look right, `M 1 2 C 2 3 Z M 1 0 Z` - much better