feat(ci): Add CIFuzz integration

[DavidKorczynski]

Add CIFuzz workflow action to have fuzzers build and run on each PR.
This is a service offered by OSS-Fuzz, on which open62541 already runs.

[CLAassistant]

All committers have signed the CLA.

[DavidKorczynski]

I think the issue with CIFuzz happens because of an issue in CIFuzz itself google/oss-fuzz#6755

I fixed this in google/oss-fuzz#6922 but am now running into fuzzer build issues:

[ 46%] Building C object CMakeFiles/open62541-object.dir/src/server/ua_subscription_events.c.o        
[ 71%] Built target open62541-object                                                               
[ 71%] Linking C static library bin/libopen62541.a                                               
[ 71%] Built target open62541                                                                               
Consolidate compiler generated dependencies of target open62541-fuzzplugins                                             
[ 84%] Built target open62541-fuzzplugins                                                               
Consolidate compiler generated dependencies of target fuzz_json_decode_encode                                                       [ 85%] Linking CXX executable /out/fuzz_json_decode_encode
/usr/bin/ld: ../../CMakeFiles/open62541-object.dir/src/server/ua_server.c.o: in function `UA_Server_delete':           
/src/open62541/src/server/ua_server.c:204: undefined reference to `UA_EventLoop_stop'                                 
/usr/bin/ld: /src/open62541/src/server/ua_server.c:(.text.UA_Server_delete[UA_Server_delete]+0x374): undefined reference to `UA_Even
tLoop_getState'                                                                                                                 
/usr/bin/ld: /src/open62541/src/server/ua_server.c:208: undefined reference to `UA_EventLoop_run'
/usr/bin/ld: ../../CMakeFiles/open62541-object.dir/src/server/ua_server.c.o: in function `UA_Server_newWithConfig':
/src/open62541/src/server/ua_server.c:348: undefined reference to `UA_EventLoop_setLogger'                           
/usr/bin/ld: ../../CMakeFiles/open62541-object.dir/src/server/ua_server.c.o: in function `addRepeatedCallback':
/src/open62541/src/server/ua_server.c:388: undefined reference to `UA_EventLoop_addCyclicCallback'
/usr/bin/ld: ../../CMakeFiles/open62541-object.dir/src/server/ua_server.c.o: in function `UA_Server_addTimedCallback':
/src/open62541/src/server/ua_server.c:377: undefined reference to `UA_EventLoop_addTimedCallback'
/usr/bin/ld: ../../CMakeFiles/open62541-object.dir/src/server/ua_server.c.o: in function `addRepeatedCallback':
/src/open62541/src/server/ua_server.c:388: undefined reference to `UA_EventLoop_addCyclicCallback'
/usr/bin/ld: /src/open62541/src/server/ua_server.c:388: undefined reference to `UA_EventLoop_addCyclicCallback'
/usr/bin/ld: ../../CMakeFiles/open62541-object.dir/src/server/ua_server.c.o: in function `changeRepeatedCallbackInterval':
/src/open62541/src/server/ua_server.c:408: undefined reference to `UA_EventLoop_modifyCyclicCallback'
/usr/bin/ld: /src/open62541/src/server/ua_server.c:408: undefined reference to `UA_EventLoop_modifyCyclicCallback'
/usr/bin/ld: ../../CMakeFiles/open62541-object.dir/src/server/ua_server.c.o: in function `removeCallback':
/src/open62541/src/server/ua_server.c:425: undefined reference to `UA_EventLoop_removeCyclicCallback'
/usr/bin/ld: /src/open62541/src/server/ua_server.c:425: undefined reference to `UA_EventLoop_removeCyclicCallback'
/usr/bin/ld: ../../CMakeFiles/open62541-object.dir/src/server/ua_server.c.o: in function `UA_Server_run_startup':
/src/open62541/src/server/ua_server.c:556: undefined reference to `UA_EventLoop_start'
/usr/bin/ld: ../../CMakeFiles/open62541-object.dir/src/server/ua_server.c.o: in function `UA_Server_run_iterate':
/src/open62541/src/server/ua_server.c:643: undefined reference to `UA_EventLoop_run'
/usr/bin/ld: /src/open62541/src/server/ua_server.c:644: undefined reference to `UA_EventLoop_nextCyclicTime'
/usr/bin/ld: ../../CMakeFiles/open62541-object.dir/src/server/ua_server_config.c.o: in function `UA_ServerConfig_clean':
/src/open62541/src/server/ua_server_config.c:34: undefined reference to `UA_EventLoop_getState'
/usr/bin/ld: /src/open62541/src/server/ua_server_config.c:35: undefined reference to `UA_EventLoop_getState'
/usr/bin/ld: /src/open62541/src/server/ua_server_config.c:36: undefined reference to `UA_EventLoop_stop'
/usr/bin/ld: /src/open62541/src/server/ua_server_config.c:37: undefined reference to `UA_EventLoop_getState'
/usr/bin/ld: /src/open62541/src/server/ua_server_config.c:38: undefined reference to `UA_EventLoop_run'
/usr/bin/ld: /src/open62541/src/server/ua_server_config.c:37: undefined reference to `UA_EventLoop_getState'
/usr/bin/ld: /src/open62541/src/server/ua_server_config.c:41: undefined reference to `UA_EventLoop_delete'

.....

[jpfr]

Fixed by #4826 .
Thanks for the feature!