- created new telnet library ciUE
- using X-macro defined NR_UE_L2_STATE string array to get UE sync state
- add telnet CI to nrUE container

log module improvement: remove redundant declarations y using C macro, remove unused variables, remove unused log components, move information to smaller visibility

- centralized channel simulation documentation in channel_simulation.md
- removed redundant documentation repeated in multipled .md files
- updated links
- removed obsolete information
- introduced mermaid flowchart for rfsim
- added missing information about available options and usage
- deleted:    ../../../openair1/SIMULATION/TOOLS/DOC/devusage.md
- deleted:    ../../../openair1/SIMULATION/TOOLS/DOC/rtusage.md
- deleted:    ../../../openair1/SIMULATION/TOOLS/DOC/arch.md

related to issue #739

The function rrc_gNB_process_RRCReconfigurationComplete() does almost
nothing, we can delete it.

The variable name ue_reconfiguration_after_reestablishment_counter is
misleading, as it counts all reconfigurations; rename to make it clear.

Plugin can trigger reestablishment (on DU)
and show counters of reestablishment (on CU)

- adds function to retrieve the only UE's RNTI
- adds function to trigger reestablishment for the only UE present, or a
  specific via its RNTI
- adds function to verify the reestablishment counters

Most targets don't need the symbols from the compiled RRC ASN.1
libraries, but only the headers. In particular when compiling individual
libraries (e.g., for tests), linking the full library makes the RRC
ASN.1 libraries compile and link, when they are not needed (only headers
are needed).

For libraries that can do without these headers, don't link them.

The simulators have been changed: due to linker errors that would arise
otherwise, a lot of functions are defined in them to avoid such errors.
Some functions are also defined in header files; in this commit, we
define most functoins in nr_dummy_functions.c, which is compiled in, not
by including the C file, but by adding it to the target in
CMakeLists.txt

- nr_dlsim+nr_ulsim need NR_IF_Module_init(), so it cannot be in
  nr_dummy_functions, but the others need it
- Link correcr NR_IF_Module_init() into these simulators, and reduce
  overall link list
- Correctly link remaining simulators

- Add oai header to typescript and html sources, add support to commands
  requiring two parameters, add more helpfiles
- Fix help bug (html comments not removed from tooltips)
- Fix backend build problem and 2 warnings
- Correctly initialize variables in nr_phy_scope.c
- Use add_subdirectory for websrv cmake build
- correctly link to asn1_lte_rrc and asn1_nr_rrc
- fix bug: correctly recognize npm packet
- only configure targets if explicitly asked for by users
- use add_subdirectory
- Use add_subdirectory for telnet cmake build
- Minor cleanup in build_oai
- Move softscope build in dedicated CMakeLists, and comment out
  DEBUG_MAC_INTERFACE option (not found in code)
- Make DEBUG_ASN1 a cmake only option ( no C macro) as it's not used as
  a C macro in the code, and develop align

- Remove any FlexRAN code
- Cleanup config files
- Remove LFDS7, libyaml dependencies