Update of the code with the update of some of the dependencies

[mmoqui]

Don't forget to merge before:

• Update version Jackrabbit to 2.14.3 and common-io to 1.11 Silverpeas-JCR-AccessControl#1
• Update the version of both Jackrabbit (to 2.14.3) and Tika (to 1.16) Silverpeas-Jackrabbit-JCA#1
• Dependencies update silverpeas-dependencies-bom#4

Don't forget to merge after:

• Update of the code with the update of some of the dependencies Silverpeas-Components#558
• Take into account the dependencies update Silverpeas-Assembly#15

With the update of some of the dependencies and the removal of some of very old
dependencies, some codes have been refactored:

• The application cache in the Caching Engine is now based upon the new version
  of ehcache. In its new version the element expiry mechanism has now to be
  explicitly defined. If ehcache 3 provides a default mechanism for TTL-based
  expiry or TTI-based expiry, nothing is provided to define a mechanism based
  upon both TTL and TTI as it was in ehcache 2. So a custom expiry mechanism
  is defined to implement the way the TTL-and-TTI-based expiry was
  managed in ehcache 2.
  With the new version of ehcache, any null key throws immediately
  NullPointerException. This cause problems with MessageManager that uses the
  application cache and particularely in tests. So, the tests were updated to
  initialize MessageManager and a check is performed in MessageManager when
  accessing the application cache to catch the NullPointerException exception.

• In the last version of Apache POI, the attributes are now encapsultated by
  getter. So replace all the direct attribute accesses by their counterpart
  getter.

• The iCal4J API as some subtle changes. The HTMLProperty is modified
  consequently to those changes. Timezone registry in iCal4J requires a JCache
  implementation to cache timezones. EhCache 3 provides an implementation of
  JCache but it is necessary to declare the cache-api (JCache API) dependency to
  load this implementation for the iCal4J Timezone (use of the ServiceLoader
  mechanism)

• In the new Jackson version, the null fields are now also serialized.
  Set a configuration parameter to the ObjectMapper in JSONCodec so that
  Jackson behaves like its previous versions, that is to say by omitting any null fields.

• The very old informa library to produce or to consume RSS feeds is now
  replaced by the last version of Rome. All the codes that used informa are now
  refactored to use Rome instead of informa.

• Spring social connectors are updated to their last stable version. For doing,
  as LinkedIn has migrated their OAuth mechanism to OAuth2 and discourages
  strongly the use of OAuth1, the Linked connector in Silverpeas is updated to
  use OAuth2 instead of OAuth1.

[SilverYoCha]

Merged.
Closed manually because of manual git operations performed during integration.