Closes #22

Fixes #22

- Remove IRegistry interface, and define it (for now) as an alias to RegistryEntry
- Remove reference counting from RegistryEntry, replace with std::unique_ptr
- Add move constructor/assignment to RegistryEntry

closes #5

Improve Gitlab-CI configuration

See merge request !651

Implemented a new property for IoComponentMgr to hold search patterns for direct I/O input file names (mr !646)

Implemented a new property for IoComponentMgr to hold search patterns for direct I/O input file names

Also cleaned up IoComponentMgr.h from obsolete comments

* master: (58 commits)
  revert part of GMR 526 to allow retrieval of const services
  fully deprecate DeclareFactoryEntries.h
  Prefer Gaudi::apply over direct use of std::index_sequence
  add Gaudi::apply -- an implementation of C++17 std::apply
  Add renamePFN and deletePFN methods to FileCatalog
  Fix "dereference after null check" error introduced with e6f3bc22 (mr !455)
  Fix bug introduced with 99edb6c4 (mr !420)
  Do string conversion in stream operator for AlgsExecutionStates::State
  Update release notes
  Revert "GaudiProjectConfig: Fix generated __init__ files to handle symlinks (mr !636)"
  Update release notes
  Prevent property deprecation warnings when unpickling options
  inline one-line member functions
  prefer cstdint over stdint.h
  Add check of EventIDBase assignment operator
  Implement EventIDBase ordering in a generic way
  Add v30r2 release notes
  Fix formatting
  Add release notes for v29r3
  Fix lookup for compiler path
  ...

- Add Gaudi::apply -- an implementation of C++17 std::apply
- Prefer Gaudi::apply over direct use of std::index_sequence:
    - eliminates the explicit 'two-step' call through an `invoke` member
      function required to generate an `std::index_sequence`
    - enables RVO in multi transformer case

See merge request !622

- eliminates the explicit 'two-step' call through an `invoke` member
  function required to generate an `std::index_sequence`
- enables RVO in multi transformer case

- fix "dereference after null check" error introduced with e6f3bc22 (mr
!455)
- fix "uninitialized member" error introduced with 99edb6c4 (mr !420)

https://coverity.cern.ch/reports.htm#v13572/p10041/fileInstanceId=763878155&defectInstanceId=396360325&mergedDefectId=98200

https://coverity.cern.ch/reports.htm#v13572/p10041/fileInstanceId=763879735&defectInstanceId=396360581&mergedDefectId=98201

Change

operator<<( std::ostream& s, AlgsExecutionStates::State x )

to convert to string instead of integer. The latter was nowhere used.
Use the operator in EntityState to avoid the duplicate enum-to-string
hard-coding.

This reverts merge request !636