libs : rename libcommon -> libllama-common (#21936)

* cmake : allow libcommon to be shared

* cmake : rename libcommon to libllama-common

* cont : set -fPIC for httplib

* cont : export all symbols

* cont : fix build_info exports

* libs : add libllama-common-base

* log : add common_log_get_verbosity_thold()

common/log.cpp

@@ -23,6 +23,10 @@
 
 int common_log_verbosity_thold = LOG_DEFAULT_LLAMA;
 
+int common_log_get_verbosity_thold(void) {
+    return common_log_verbosity_thold;
+}
+
 void common_log_set_verbosity_thold(int verbosity) {
     common_log_verbosity_thold = verbosity;
 }