Implement basic I/O utilities

- Read from standard input
- Implement string methods
- Get all lines
- Split by character (or no character)
- ... and many more

Start by reading the repository to find how standard input and string methods are represented. Use the issue's list as the initial scope: reading standard input, getting all lines, and splitting by a character or with no character. Done means these utilities and the remaining intended string methods are implemented and usable in Linefeed.

Written by the indexing model from the issue text.