[2027] Perform the majority of the reorg changes

[pjreiniger]

This performs the majority of the user facing changes listed in the reorg doc. This was performed by this script, which has more details on the process.

Whats included

This effort attempts to cover as much of the reorg spreadsheet as possible without major build system changes and without major code changes

Things covered in the script:

• All subprojects but glass have been moved into their new folders
• Java package renames (and paths in repo)
• C++ file moves, as well as a vast change to using .hpp instead of .h as noted here
  • NOTE, A bulk assumption was made that all files, unless the files explicitly had _c in their name was to change the file. This might be incorrect.
• C++ namespaces
• Change maven coordinates
• While not explicitly denoted in the spreadsheet, the C++ files were moved to attempt to match the java file moves.

Things NOT covered in the script, which I think are outside the scope of this initial effort

• Separate glassApp from glasslib. This is a build system change so it will be done in a follow up PR.
• Combine wpilibc and wpilibj into a common project. Again, build system change, follow up PR
• Move C++ units into the wpiunits project. Again, build system
• Some of the suggested file moves denoted in the spreadsheet are across project boundaries and need dependency chains broken before they can move
• Per an offline conversation, the serde project might not bring a whole lot of benefit, so it has been left in wpiutil with namespaces / include paths unchanged.

Process

1. Preprocess C++ and Java files to determine file moves, and calculate their
   respective changes to other files, i.e. how to change C++ include paths, or
   java package / import renames
   1b. Additional renames are applied as per this document https://docs.google.com/spreadsheets/d/1NXgby1njo7oZ9_Ezk8q6ez5VzPTXeLAVRSnB3M1TqR4/edit?gid=1323156307#gid=1323156307
   Note, some of the proposed renames require substantial build file modifications or need dependencies broken, and therefore are not covered with this script.
2. Apply the pre-processed renames and include / import fixups
   3-N. Apply some manual fixes, as well as run scripts like the linters, upstream utils, pregenerated files, etc
   N-M. Apply namespace changes. This is a combination of automated find/replace as well as hand fixes.

An intermediate file, refactor_layout_pp.json is created to track the file moves and namespace / import changes. This file can be repurposed in a simpler script to help with the upgrade process for vendors / teams

Other notes

The namespace changes were non-trivial. Since some projects (wpiutil, wpinet shared wpi::, wpimath, wpilibc shared frc::) you cannot trivially do a bulk replacement and differentiate between what belongs to what new nested namespace. Furthermore, there is no consistency in C++ if files have using namespace XXX; vs namespace XXX {}. Also there was no consistency between when fully qualified names were used vs non fully qualified.

To address these things a couple of function / types are defined a prior to get replaced before bulk actions happen. In addition, everything, in both .cpp files and .h files will use fully qualified namespaces, regardless of the fact that they all now share a common wpi:: prefix.

Some of the regex's could probably be combined / simplified / more robust, but it works for a temporary script.

The script is not intended to be located inside of allwpilib, but I thought this would be the best way to review it.

[github-actions]

This PR modifies commands. Please open a corresponding PR in Python Commands and include a link to this PR.

[daltzctr]

Can a summary/list of the changes in this reorg be added to the PR description or the comment? Just to make it a bit easier when updating dependent references

[sciencewhiz]

I'm also hoping to make a watered down version of the script that can hopefully handle the vast majority of the renames for vendors and teams

The vscode importer does regex replacements, so if it's possible to describe the changes that way, teams wouldn't need to run a separate script.