Bug 29781: Enable capture groups in batch item modification

Bug 29781: Enable capture groups in batch item modification

This patch adds support for regular expression capture groups in
MarcModificationTemplates.

We escape double quotes in the replacement string, then quote the whole
string before applying the `ee` modifier to the final regex
application.

See https://blog.james.rcpt.to/2010/10/25/perl-search-and-replace-using-variables/
for further details.

Test plan
1) Attempt to use capture groups in your regular expression based
   batch item modification and note it does not work.
2) Apply the patch and try again, this time the capture group
   should yield the expected results.
3) Run t/SimpleMARC.t and confirm the tests still pass.

Signed-off-by: Andrew Fuerste-Henry <andrew@bywatersolutions.com>
Signed-off-by: Jo Hunter <jhunter@clicweb.org>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>