More recipes for how-to section

[awvwgk]

The how-to section needs more recipes for using stdlib:

Basic installation instructions:

• buildings stdlib from source via CMake (mainly for contributors/developers)
• install stdlib from distribution channels, like conda-forge
• use stdlib via fpm

Problems solved by stdlib

• converting integer/real values to strings with to_string
• reading and writing npy files
• sorting and searching a list of strings
• reading a whole file into a string or list of strings
• working on bytes or bitarrays using the bitsets types (instead of unsigned arithmetic)