Currently the value set via OIDCMemCacheConnectionsTTL is interpreted as
microseconds and not as seconds. Correctly interpret this value as seconds
via ap_timeout_parameter_parse and create the needed infrastructure to parse
similar timeout fields in the future.

* src/cache/memcache.c:
  - Change type of ttl to apr_interval_time_t.
  - The default value is now returned via oidc_cfg_cache_memcache_ttl_get.
  - Adjust format strings for apr_interval_time_t printing.

* src/cfg/cache.c:
  - Generalize  OIDC_CFG_MEMBER_FUNCS_CACHE_INT_EXT macro to
    OIDC_CFG_MEMBER_FUNCS_CACHE_PARSE which allows to specify the parsed
    type.
  - Add OIDC_CFG_MEMBER_FUNCS_CACHE_TIMEOUT macro which parses
    apr_interval_time_t values via oidc_cfg_parse_timeout_min_max.
  - Shorten maximum TTL via OIDC_CACHE_MEMCACHE_CONNECTIONS_TTL_MAX to 4292
    seconds.
  - Change default via OIDC_DEFAULT_CACHE_MEMCACHE_CONNECTIONS_TTL from 0
    to 60 seconds.
  - Use OIDC_CFG_MEMBER_FUNCS_CACHE_TIMEOUT instead of
    OIDC_CFG_MEMBER_FUNCS_CACHE_INT macro for memcache_ttl field.

* src/cfg/cache.h:
  - Change type of memcache_ttl from int to apr_interval_time_t.

* src/cfg/cfg.h:
  - Define OIDC_CONFIG_POS_TIMEOUT_UNSET to -2 (-1 might be used for unlimited
    timeout).

* src/cfg/cfg_int.h:
  - Change type of memcache_ttl from int to apr_interval_time_t.

* src/cfg/parse.c:
  - Add oidc_cfg_parse_timeout_min_max to parse a timeout string via
    ap_timeout_parameter_parse into an apr_interval_time_t if it is in a valid
    min/max range.

* src/cfg/parse.h:
  - Add prototype for oidc_cfg_parse_timeout_min_max

Signed-off-by: Ruediger Pluem <[email protected]>