CLEANUP: ssl/cli: use a local context for "commit ssl {ca|crl}file"

CLEANUP: ssl/cli: use a local context for "commit ssl {ca|crl}file"

These two commands use distinct parse/release functions but a common
iohandler, thus they need to keep the same context. It was created
under the name "commit_cacrlfile_ctx" and holds a large part of the
pointers (6) and the ca_type field that helps distinguish between
the two commands for the I/O handler. It looks like some of these
fields could have been merged since apparently the CA part only
uses *cafile* and the CRL part *crlfile*, while both old and new
are of type cafile_entry and set only for each type. This could
probably even simplify some parts of the code that tries to use
the correct field.

These fields were the last ones to be migrated thus the appctx's
ssl context could finally be removed.