tools: ship the final man pages directly, no more man pages templates

tools: ship the final man pages directly, no more man pages templates

Don't use templates for the man pages, the API version change is a rare
event, so it's not really worth keeping in place the "sed" boilerplate
to have it set at build time.

Shipping the final man pages directly also makes it easer to install the
man pages with meson (in a future commit).

Note that now all the occurrences of the programs names have the API
version as a suffix.

Traditionally the example command lines looked like:

  gst-launch ...

Now they look like:

  gst-launch-1.0 ...

This reflects the actual programs names and makes it easier to copy and
paste the example commands.

Also, the .gitignore file is adjusted not to ignore the final man pages
anymore.

You may need to clean your src/build directory before pulling in this
patch.

https://bugzilla.gnome.org/show_bug.cgi?id=773917