misc: vendor libjamiclient into 'src/libclient/'

This is libjamiclient from the jami-libclient.git repository as of
767c45b8b09806ac05cbada720864df93588c047, with the following changes:

* src/libclient/newaccountmodel.cpp:
(NewAccountModelPimpl::removeFromAccounts): The lock wait inside
'#ifdef CHK_FREEABLE_BEFORE_ERASE_ACCOUNT' was not updated when the
type of 'accounts' was changed over the years from this:
std::map<std::string, account::Info>
to this:
std::map<QString, std::pair<account::Info, std::shared_ptr<Database>>>
Basically we need to get the 'first' of the pair for 'account::Info'.
So we now do that.

* src/libclient/avmodel.cpp:
* src/libclient/callbackshandler.cpp:
* src/libclient/contactmodel.cpp:
* src/libclient/conversationmodel.cpp:
* src/libclient/database.cpp:
* src/libclient/namedirectory.cpp:
* src/libclient/newaccountmodel.cpp:
* src/libclient/newcallmodel.cpp:
* src/libclient/newdevicemodel.cpp:
* src/libclient/peerdiscoverymodel.cpp:
* src/libclient/pluginmodel.cpp:
* src/libclient/smartinfohub.cpp:
* src/libclient/vcard.h:
* src/libclient/authority/storagehelper.cpp:  Replace Qt's 'foreach'
with 'Q_FOREACH' and its 'emit' with 'Q_EMIT' because in the client-qt
code base we have '-DQT_NO_KEYWORDS' to avoid conflicts with other
libraries we use.

* cmake/FindLibJami.cmake: Import cmake/FindRing.cmake from the
jami-libclient.git repository.  Then, rename RING_BUILD_DIR to
LIBJAMI_BUILD_DIR (though the old name is still supported for now).
Also update other references of Ring to Jami.  Further, add additional
calls to 'find_library' to make sure specified local paths for libjami
are checked before system-wide ones (in case of older/obsolete libjami
being available system-wide, which might happen on GNU/Linux systems).

* translations/lrc_*.ts: Import translation files from the libclient
repository.  The message location paths were corrected by running
"sed -i 's|../src|&/libclient|g' lrc_*.ts" in 'translations/'.

.tx/config: Add section for the newly-imported libclient translations.

* CMakeLists.txt: Reformat, plus various fixes and cleanups, such as
changing indentation to 2 spaces and wrapping lines at 70 characters,
renaming the parent directory of translations from 'ring' to 'jami',
and using all lowercase function calls.  Also add copyright headers.

* src/app/appsettingsmanager.cpp:
(AppSettingsManager::loadTranslations):
* src/app/utilsadapter.cpp (UtilsAdapter::supportedLang): Update to
adapt to the renaming of the parent directory of translations from
'ring' to 'jami'.

GitLab: #748
Change-Id: I86e3b0fb30e554755023e7b858b6a0d132cd59ab