E3-1402

See merge request !152

E3-615: Replace `iocsh` shell script with python script

See merge request !147

The entry point for the e3 IOC shell has been rewritten from being a shell/bash
script to instead be in python. Together with this comes a plethora of changes -
see the CHANGELOG for a more comprehensive description.

E3-1378: Fix make clean

See merge request e3/e3-require!150

This is due to relying on the intermediate rules
```
build-%: | $(COMMON_DIR)
```
(etc.) which trigger's Make's "intermediate file cleanup". The
simplest solution is to make a clear dependency on the common
directory instead of the implicit one.

Note that this is similar to how this is done in EPICS base and is
necessary: we allow for arch-specific dependencies so this really
ought to be done after T_A is defined. Moreover, it is necessary to
ensure that we don't trigger an error if a dependency is not defined
correctly (which has cause `make clean` to fail!)

Add some missing entries into changelog

See merge request e3/e3-require!151

E3-1145: Remove `ARCH_FILTER` in favour of `EXCLUDE_ARCHS`

See merge request e3/e3-require!149

CE-1958: Remove enabling of core dumps

See merge request e3/e3-require!148

Done in order to not generate infinitely large files, which otherwise might cause a system to run out of memory.

The soft limit is set to 100 MB.

Set EPICS base version in `.gitlab-ci.yml` instead of project settings,
to make it more transparent as well as to make it work also for forks.

E3-1160: Install license files automatically

See merge request e3/e3-require!146

Build essioc and test that it loads correctly

See merge request e3/e3-require!145

Most EPICS modules need the license file to be distributed with
binaries. This commits fixes it by automatically installing every
license file on the project.

Mixed rewrites of require functions

See merge request e3/e3-require!144

First change is to remove minsize, we don't need to calculate the size
previously anymore as we don't change the pfield directly.
Also, remove the get_array_info call. This was mandatory to be able to
update the pfield, we don't do it anymore.

The E3 does not use modules linked out of require so this code is
superfluous here. It was used to register require itself however the
code complexity was not justified for such simple task. To fulfill
this a simpler function was added just to register require.

This function was writing the buffers directly instead of using
standard EPICS API to update the record. Using the API is clearer
and safer.

E3-641: Remove "make epics" rules

See merge request e3/e3-require!143

These were intended originally to allow a hybrid build system: you
could build an e3 module as the dynamically loaded shared library,
but you could also run `make epics` and build it as a vanilla EPICS
module.

However, this has never really worked, nor has it been supported. It
may in the future be supplanted by properly using the EPICS build
rules in lieu of the use of driver.makefile, but that is for a future
change.

E3-1243: Enforce strict conditions on module existence

See merge request e3/e3-require!142

Originally we simply warned if `FOO_DEP_VERSION` did not refer to a real
module; this was necessary as some modules had legacy (non-e3) dependencies
defined this way. However, this has the unfortunate side-effect that missing
_modules_ would "pass" the build, with a failure only happening if some
version of the module existed (but not the correct one).

E3-1214: Fix usage of string functions

See merge request e3/e3-require!139

E3-1132: Remove record search from expandDBD

See merge request e3/e3-require!135

See https://github.com/paulscherrerinstitute/require/commit/134aed5a5e618ae12a95134862401f1dcc92c834
for some context. Instead of searching recursively through .dbd files, one
can instead just filter source files for `%Record.(c|cc|cpp)`. This simplifies
the special python/tcl/pl script to handle dbd files.