- comments to improve readability of the code
- Clang formatting of E1 / RRC (partial)

- new folder dedicated to E1AP docs
- new file to document E1AP procedures

- PDCP reestablishment on CUCP (DRBs) triggering Bearer Context Modification procedures over E1
- Performing PDCP reestablishment for requested DRBs on CUUP
- Introduced function to notify re-establishment to CU-UP
- removed call to PDCP reestablishment for the DRBs on CUCP (it's done on CUUP)

cuup_notify_reestablishment:

- to fetch PDU session to setup in E1 following logic as in e1_send_bearer_updates
- fill bearer context modification request with stored F1-U tunnel information
  during E1 reestablishment, otherwise it would initialized to 0 by default
- update GTP tunnel with the stored configuration after E1 reestablishment

- info coming from UE context setup/modification response messages in RRC

The previous code removed the "secondary UE" data (about DU association,
DU UE ID, associated CU UP), and only filled the F1-related data. In
other words, the associated CU-UP was lost. This commit reworks this
piece of code to retrieve old data, and update the relevant data without
destroying other.

- many structs and definitions are overlapping between the two different E1 procedures
- introduced naming specific to E1 Bearer Context Modification to improve readability
- grouped SDAP and PDCP configuration IEs for better reusability and readability
- introduced functions to set and get default PDCP config (DRBs and Bearer Contexts)

find_or_next_pdu_session:
- find_or_next_pdu_session refers to the E1 Bearer Context Modification Request
-- therefore it has to return pdu_session_to_mod_t* and takes in input e1ap_bearer_mod_req_t *

see !MR2545 for more context

- according to specs, in NR there are 4 SRBs
- in OAI the relevant define is used in the RRC procedures
- this commit harmonizes code by removing redundancy

- the goal is to improve maintanability

CI: Integration Branch 2024 week 08

See merge request oai/openairinterface5g!2585

* !2540 NR UE max MIMO layers from UEcap
* !2554 NR UE RRC minor improvements
* !2563 Add missing backtick for proper code style in README.md
* !2567 Avoid integer overflows, buffer overflows, in channel levelling
* !2574 NR UE fix for configuring coreset0 and SS0
* !2575 NR UE fix init PDCP phy-test
* !2551 NR UE improvements for contention resolution timer
* !2570 CI: Replace nrmodule2 by up2

Merge remote-tracking branch 'origin/fix-multiple-inexact-computations-in-nr_dlsch_channel_level' into integration_2024_w08

Add missing backtick for proper code style in README.md: on behalf of Roger Pueyo Centelles, MR 2563
Signed-off-by: Raphael Defosseux <raphael.defosseux@eurecom.fr>

UBsan fails with errors without this commit. The commit changes:

- avoid two possible integer overflows in nr_dlsch_channel_level() and nr_dlsch_channel_level_median()
- nr_dlsch_channel_level_median() is simplified
- use MAX_ANT in avg to handle more than 4x4 config

feat(doc): suggested changes: realtime tuned profile, kthread_cpus formulation and further details in PTP pining

feat(doc): update O-RAN 7.2 doc: details in kernel thread isolation, kernel thread isolation for solving PTP clock lag, PCI address of VFs

Integration: 2024.w06

Closes #733 and #732

See merge request oai/openairinterface5g!2564

* !2490 reworking configuration of LogicalChannelConfig at MAC UE
* !2548 NR UE MSG3 buffer
* !2556 Support RC SM aperiodic subscription for "UE RRC State Change"
* !2557 fix duplicate call of RCconfig_NR_L1
* !2550 use pointer to structure instead of module_id inside MAC
* address #733
* !2560 chore(ci): force rebuild of ran-base for integration branches
* !2495 Sidelink configuration passed from RRC->MAC
* !2220 L1 tx thread
* !2559 FH 7.2 improvements
* !2566 Provide right E1 instance when creating E2 agent in CU-UP
* !2513 Update NR SA tutorials

CUuniqInstance is also used for GTP module identification, which
uses the UDP server socket as its ID. This leads to arbitrary IDs (>0),
which is wrong.