Move config & keygen to a dedicated binary

This moves the config generation from the main session-router binary
into a dedicated session-router-config binary, which can now:

- `-c` generate a full client config
- `-r` generate a router config
- `-e` generate an embedded config
- `-H` generate a hidden service config (= client config, but with DNS
  disabled, more inbound paths, and a persistent key)
- `-k` generates a keypair file
- `-s` show the pubkey from a keypair file

along with some other flags that let you tweak the generated file.

Along the way this reworks several related things:

- config "overrides" that could be set via RPC are now gone.  They
  seemed like a privelege escalation (because a user could make
  permanent changes overriding the settings in the admin-protected
  config file).  Also they were quite broken because if you tried to
  actually "override" a setting it just errored with an error about
  specifying a value more than once, bricking lokinet; and for
  multi-options it could only append but not replace.  (These issues
  could be fixed, but don't seem worth it given the first issue).

- removed a bunch of related override saving code.

- Untangled a weird relationship between
  Config/ConfigDefinitions/Parser.

- Drop `ConfigGenParameters` which was really just two values, one of
  which was wrong (the data-dir, as it referred to the default rather
  than actual) and the other of which was already in the
  ConfigDefinitions.

- Made all paths the config (e.g. unbound hosts, key file) properly
  resolve relative to the config file dir.  Previously they were all
  wrong in different ways: some relative to cwd, some relative to
  data-dir, some relative to the *default* data_dir fallback if you
  don't specify a datadir.

- Make the config file a required argument when launching
  session-router, and never auto-vivify it.

- Make the keyfile no longer auto-vivify: if a keyfile is specified that
  doesn't exist it is now an error.

- Remove many deprecated config options as we no longer are aiming to be
  a seamless upgrade from Lokinet.

- Rename "Deprecated" in the config to "Obsolete" to better reflect what
  it does (i.e. warn and ignore).

- Remove "undeclared" ini handlers.  They were gross, and the last use
  of it (for unbound options) is now gone.

Author: jagerman

src/CMakeLists.txt

@@ -190,8 +190,8 @@ endforeach()
 configure_file("nodedb-bootstraps.cpp.in" "${CMAKE_CURRENT_BINARY_DIR}/nodedb-bootstraps.cpp" @ONLY)
 target_sources(session-router-nodedb PRIVATE "${CMAKE_CURRENT_BINARY_DIR}/nodedb-bootstraps.cpp")
 
-# session-router-config is for all configuration types and parsers
-session_router_add_library(session-router-config
+# session-router-conf is for all configuration types and parsers
+session_router_add_library(session-router-conf
   config/config.cpp
   config/definition.cpp
   config/ini.cpp
@@ -209,26 +209,26 @@ session_router_add_library(session-router-path
 
 if(SROUTER_DEBUG_PATH_SEED)
   target_compile_definitions(session-router-nodedb PRIVATE SROUTER_DEBUG_PATH_SEED)
-  target_compile_definitions(session-router-config PRIVATE SROUTER_DEBUG_PATH_SEED)
+  target_compile_definitions(session-router-conf PRIVATE SROUTER_DEBUG_PATH_SEED)
   target_compile_definitions(session-router-path PRIVATE SROUTER_DEBUG_PATH_SEED)
 endif()
 
 # Link libraries to their internals
 target_link_libraries(session-router-nodedb PUBLIC session-router-addressing session-router-cryptography)
 target_link_libraries(session-router-contact PUBLIC session-router-dns)
 if(SROUTER_FULL)
-  target_link_libraries(session-router-rpc PUBLIC session-router-contact session-router-config)
+  target_link_libraries(session-router-rpc PUBLIC session-router-contact session-router-conf)
 endif()
 target_link_libraries(session-router-addressing PUBLIC session-router-utils session-router-cryptography session-router-contact session-router-ip)
-target_link_libraries(session-router-config PUBLIC session-router-cryptography session-router-addressing)
+target_link_libraries(session-router-conf PUBLIC session-router-cryptography session-router-addressing)
 if(SROUTER_FULL)
   target_link_libraries(session-router-platform PUBLIC session-router-cryptography session-router-ip)
-  target_link_libraries(session-router-config PUBLIC session-router-exit-auth)
+  target_link_libraries(session-router-conf PUBLIC session-router-exit-auth)
 endif()
 target_link_libraries(session-router-dns
   PUBLIC
   session-router-cryptography
-  session-router-config
+  session-router-conf
 )
 if(SROUTER_FULL)
   target_link_libraries(session-router-dns PUBLIC session-router-platform)
@@ -241,7 +241,7 @@ target_link_libraries(session-router-path
 
 target_link_libraries(session-router-core-utils 
   PUBLIC 
-  session-router-config
+  session-router-conf
   session-router-dns
 )