Closes GH-4470

- Git is used for moving existing extensions to PECL
- PHP versions with the PHP 7.4 examples
- Some minor tweaks here and there
- Mention re2c also
- Mention Docker image as a helper tool

This enhances the makidst script:
- integrate both snapshot and makedist scripts together
- add help and options
- generated files are created in the php-src repository directly
- other minor enhancemenets such as CS fixes
- functionality moved from the Makefile to only shell script
- Add missed patching of the Zend Parsers to the main build step
- Add all *.tmp files to gitignore

The acinclude.m4 file is in a usual Autotools build processed with
Automake's aclocal tool. Since PHP currently doesn't use Automake and
aclocal this file can be moved into the build directory. PHP build
system currently generates a combined aclocal.m4 file that Autoconf
can processes automatically.

However, a newer practice is writing all local macros in separate
dedicated files prefixed with package name, in PHP's case PHP_MACRO_NAME
and putting them in a common `m4` directory. PHP uses currently `build`
directory for this purpose.

Name `php.m4` probably most resembles such file for PHP's case.

PHP manually created the aclocal.m4 file from acinclude.m4 and
build/libtool.m4. Which is also not a particularly good practice [1], so
this patch also removes the generated alocal.m4 usage and uses
m4_include() calls manually in the configure.ac and phpize.m4 files
manually.

- sort order is not important but can be alphabetical
- list of *.m4 files prerequisites for configure script generation
  updated
- Moving m4_include() before AC_INIT also removes all comments starting
  with hash character (`#`) in the included files.

[1] https://autotools.io/autoconf/macros.html

Checked and quickfixed with Markdown linter
- 80 columns line width (~)
- code highlighting
- ...

Some most obvious outdated content updated a bit more.

- Markdown
- CS syncs
- Some partial readability fixes
- The protocol hasn't been changed

This syncs the latest version and the PHP-7.4 version release process
docs.