package/readline: disable bracketed paste by default

package/readline: disable bracketed paste by default

As of readline 8.1, "bracketed paste" is enabled by default. However,
the feature causes control characters to appear in captured (telnet)
session output. This can throw off pattern matching if the output is to
be processed by scripts.

Let's keep the previous default of leaving this feature disabled and
provide a configuration option for users to enable it.

Signed-off-by: Markus Mayer <mmayer@broadcom.com>
[yann.morin.1998@free.fr:
  - explicit enable/disable
  - no indentation in conditional block
  - rewrap help text
]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>