Refactored git invocation.

Refactored git invocation from `elwiki-history-page' into a separate
function, `elwiki--get-commits', which has been placed in a new file
for Git-wrapper functions.
Refactored git committing code.

Refactored the git-commit invocation from `elwiki--save-request' into
a separate function.  Now all (direct) git invocations are in a
separate file of wrapper functions.
Fixed missing unquote.

The variable `page-info' was not unquoted in the editor esxml.
Merge "missing unquote" fix from master into actions.