Changes to `files` promise in `copy_from` attribute:

- The new file (i.e., `<FILENAME>.cfnew`) is now created with correct
  permission during remote copy. Previously it would be created with
  default permissions.
- The destination file (i.e., `<FILENAME>`) is no longer deleted on
  backup during file copy.  Previously it would be renamed to
  `<FILENAME>.cfsaved`, causing the original file to dissappear. Now an
  actual copy of the original file with the same permissions is created
  instead.

As a result, there will no longer be a brief moment where the original
file is inaccessible.

Ticket: ENT-11988
Changelog: Commit
Signed-off-by: Lars Erik Wik <[email protected]>
(cherry picked from commit 224ccc3)

When running cppcheck in static checks, we use `-i
libpromises/cf3lex.c` in order to make cppcheck ignore the
generated cf3lex.c file. However, the new version of cppcheck
ignores this option and fails on issues found in the file.

However, we don't want this file or any other generated files
except for bootstrap.inc which contains the bootstrap policy. So
we can run `make clean` and `make -C libpromise/ boostrap.inc`
before running cppcheck to get a cleaner environment.

(cherry picked from commit e9cfa41)
Signed-off-by: Lars Erik Wik <[email protected]>

```
error: externally-managed-environment
```

Since this is a container, it should be OK to potentially break system
packages.

Ticket: None
Changelog: None
Signed-off-by: Lars Erik Wik <[email protected]>
(cherry picked from commit 0195e21)

libncurses5 was not available in the noble repository, but maybe
libncurses6 will work.

```
E: Unable to locate package libncurses5
```

Ticket: None
Changelog: None
Signed-off-by: Lars Erik Wik <[email protected]>
(cherry picked from commit 4d1944a)

```
checking for pcre_exec in -lpcre... no
configure: error: Cannot find PCRE
```

Ticket: None
Changelog: None
Signed-off-by: Lars Erik Wik <[email protected]>