Document better the requirements for a succesful install

[gggeek]

The dependencies listed at the bottom of the readme could be made more clear by listing the exact ubuntu packages required, at least on a stock ubuntu. Atm it is not very clear which of the requirements is an actual package to install, and which one is not.

This is the minimal list of packages I needed to install, on a 'plain' ubuntu Jammy container, in order to get the built php to run:

 DEBIAN_FRONTEND=noninteractive apt-get install -y \
            curl \
            enchant-2 \
            imagemagick \
            libc-client2007e \
            libcurl3-gnutls \
            libmcrypt4 \
            libodbc1 \
            libpq5 \
            libqdbm14 \
            libtinfo5 \
            libxpm4 \
            libxslt1.1 \
            mysql-common \
            sudo \
            zstd

On Focal, enchant-2 has to be replaced by enchant