make config.nims behave like nim.cfg in terms of where these scripts are searched / run (#8682)

* run project config.nims if exists, then inputfile.nims if exists
* ~/.config/nim/config.nims can now be used
* also check in getSystemConfigPath for config.nims
* refactor handleCmdLine for nim and nimsuggest

compiler/options.nim

@@ -54,10 +54,10 @@ type                          # please make sure we have under 32 options
     optGenMapping,            # generate a mapping file
     optRun,                   # run the compiled project
     optCheckNep1,             # check that the names adhere to NEP-1
-    optSkipConfigFile,        # skip the general config file
-    optSkipProjConfigFile,    # skip the project's config file
-    optSkipUserConfigFile,    # skip the users's config file
-    optSkipParentConfigFiles, # skip parent dir's config files
+    optSkipSystemConfigFile,  # skip the system's cfg/nims config file
+    optSkipProjConfigFile,    # skip the project's cfg/nims config file
+    optSkipUserConfigFile,    # skip the users's cfg/nims config file
+    optSkipParentConfigFiles, # skip parent dir's cfg/nims config files
     optNoMain,                # do not generate a "main" proc
     optUseColors,             # use colors for hints, warnings, and errors
     optThreads,               # support for multi-threading
@@ -391,6 +391,7 @@ const
   TexExt* = "tex"
   IniExt* = "ini"
   DefaultConfig* = "nim.cfg"
+  DefaultConfigNims* = "config.nims"
   DocConfig* = "nimdoc.cfg"
   DocTexConfig* = "nimdoc.tex.cfg"