Documentation added and fixed

- javadoc fixes in AttributesManager and AttributesManagerBl
- documentation added and fixed in rpc, AttributesManagerMethod
Updated readme files

- Added readme for perun-rpc
- Updated readme for services and DB
REGISTRAR: do not offer joining identities when user is known

- Backported and modified change from upstream/productionElixirFix.
  When checking for similar users, if user is known (by session or
  actor/extSource) we don't have to offer joining, since perun will
  join application on approval.

  Case when user is known by actor/extSource but not session is when
  user entry was created by previous application with auto-approval
  but session was not updated in GUI (linked app forms).

  Original version returned "no match" for any unknown user, which is not good.
  Check is not performed for non-authz users on GUI side, but this logic
  must be kept in registrar for users with federated identities which we can join
  and which might be found by name or email.
Documentation fix
parm fix in rpc

- removeAlsoUserFacilityAttributes changed to workWithUserAttributes
Documentation added and fixed
GUI: Remove common application form header (kept in menu).
Documentation added & fixed - attributes

- javadoc fixes in AttributesManager and AttributesManagerBl
- documentation added and fixed in rpc, AttributesManagerMethod
- parm fix in rpc - removeAlsoUserFacilityAttributes changed to workWithUserAttributes
Documentation added & fixed - rpc Au to Ge

- added documentation mostly in rpc, but also in core and tasks-lib
Merge pull request #434 from Simcsa/javadoc

Documentation added and fixed
REGISTRAR,GUI: Support for Heading and Timezone in app form

- Added new form item HEADING, which will be used as customizable
  heading of application form. Content is considered as HTML.

- HEADING is not saved with submitted application form.

- HTML_COMMENT and HEADING now have customized language pages
  on app form settings, since they only contain label and not
  error or help text.

- Added new form item TIMEZONE, which is pre-filled with
  existing timezones in GUI and user can manually select
  one or select "Not selected" option. When required, user
  must select one of timezones.
  Form item still must be manually linked to proper attribute,
  which is urn:perun:user:attribute-def:def:timezone.

- Fixed "onChange" behavior of all selection boxes on application
  form, since their validation was previously performed only on
  form submission. It's now performed on any selection change.
GUI: removed unused style for H1
Merge pull request #457 from zlamalp/style

GUI: removed unused style for H1
Merge pull request #456 from zlamalp/headerSupport

REGISTRAR,GUI: Support for Heading and Timezone in app form
Merge pull request #454 from zlamalp/backport

REGISTRAR: do not offer joining identities when user is known
If sending error to RT, try to get mail also from AdditionalInformation

 - move emailPattern from modules to Utils.java
 - add code using emailPattern and reading data from
   session.getAdditionaInformation to RTMessageManagerBlImpl
 - remove unused imports
Merge pull request #459 from stavamichal/getMailFromSessionWhenReportingToRT

If sending error to RT, try to get mail also from AdditionalInformation
GUI: Redirect to targetexisting when user can't extend membership in VO
Merge pull request #460 from zlamalp/target

GUI: Redirect to targetexisting when user can't extend membership in VO
GUI: allow rotation