Hide Service interfaces from users

[Dr15Jones]

Many framework Services are not meant to be called by users. By removing their headers and putting their source code in the plugins directory it is now impossible for users to access them.

[cmsbuild]

A new Pull Request was created by @Dr15Jones (Chris Jones) for CMSSW_8_0_X.

It involves the following packages:

FWCore/Services
SimGeneral/MixingModule

@smuzaffar, @civanch, @Dr15Jones, @mdhildreth, @cmsbuild, @davidlange6 can you please review it and eventually sign? Thanks.
@Martin-Grunewald, @wddgit, @wmtan this is something you requested to watch as well.
@slava77, @Degano, @smuzaffar you are the release manager for this.

Following commands in first line of a comment are recognized

• +1|approve[d]|sign[ed]: L1/L2's to approve it
• -1|reject[ed]: L1/L2's to reject it
• assign <category>[,<category>[,...]]: L1/L2's to request signatures from other categories
• unassign <category>[,<category>[,...]]: L1/L2's to remove signatures from other categories
• hold: L1/all L2's/release manager to mark it as on hold
• unhold: L1/user who put this PR on hold
• merge: L1/release managers to merge this request
• [@cmsbuild,] please test: L1/L2 and selected users to start jenkins tests
• [@cmsbuild,] please test with cms-sw/cmsdist#<PR>: L1/L2 and selected users to start jenkins tests using externals from cmsdist

[Dr15Jones]

please test

[cmsbuild]

The tests are being triggered in jenkins.
https://cmssdt.cern.ch/jenkins/job/ib-any-integration/10412/console

[Dr15Jones]

@davidlange6 the simulation signature is only needed because I had to remove an unnecessary include of FWCore/Services/src/Memory.h from files under control by simulation.

[Dr15Jones]

+1
assuming everything compiles correctly

[cmsbuild]

+1
Tested at: b2a39c2
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-12860/10412/summary.html

The following merge commits were also included on top of IB + this PR after doing git cms-merge-topic:
edc7357
be91645
9ae5e58
f14457d
85922e4
You can see more details here:
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-12860/10412/git-log-recent-commits
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-12860/10412/git-merge-result

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-12860/10412/summary.html