put meson.build.pw in php-source directory

possible lines:
# Standalone Application without dependencies
bin = show_mem_usage.php -> show_mem_usage

# Application with library binding
bin = show_mem_usage.php -> show_mem_usage (library1:class1,library2:class2)

# Application with JIT-enabled (only for code, not for libraries) library binding
bin-jit = show_mem_usage.php -> show_mem_usage

# Library with dependency from class2 on class1
class = class1.php -> class1 (externlib:classname)
class = class2.php -> class2 (class1)
lib = class1,class2 -> library

# Class with JIT execution
class-jit = class2.php -> class2

# Strip File (insert to /bin/exe) (Plain PHP Execute)
strip = code.php -> exe

# Strip File (insert to /usr/share/php/diffget/diffget_server.php) - File will not be executable!
strip(/usr/share/php/diffget) = diffget_server.php -> diffget_server.php

# Bin File (insert into folder) - File will be executable
bin(/folder) = asd.php -> asd

# Create a php opcode file - File will not be executable # NOT USED ANYMORE? CAN BE DELETED?
opcode(/usr/path...) = server.php -> server.phpop

# Create etc config maintainer
etc(/etc/php/fpm-php*/php.ini)=php_fpm-php_phpini.php->php_fpm-php_phpini (libpwgeneral:pwetc)

# Create Extension for PHP-FPM (class pw_diffget_server (from same project)
class = diffget_server_src.php -> pw_diffget_server (pwgeneral:pwgeneralcopyright)
lib = pw_diffget_server -> pw_diffget_server_lib
fpmext = pw_diffget_server_lib:pw_diffget_server -> diffget_server