MEDIUM: tcpcheck: Add parsing support for healthcheck sections

MEDIUM: tcpcheck:  Add parsing support for healthcheck sections

tcpcheck_ruleset struct was extended to host a config part that will be used
for healthcheck sections. This config part is mainly used to store element
for the server's tcpcheck part.

When a healthcheck section is parsed, a ruleset is created with its name
(which must be unique). "*healthcheck-{NAME}" is used for these ruleset. So
it is not possible to mix them with regular rulesets.

For now, in a healthcheck section, the type must be defined, based on the
options name (tcp-check, httpchk, redis-check...). In addition, several
"tcp-check" or "http-check" rules can be specified, depending on the
healthcheck type.