proton-j : Upgrade BouncyCastle

[JemDay]

Changed to use a dependency.
Removed 'reflective' constructs.
Verified correct test operations with BC 1.48 and 1.54

[JemDay]

I'm not sure what the CI build is doing to cause it to fail but i can confirm that "mvn clean test" works for me from the command line .. see attached
build-log.txt

[gemmellr]

The CI builds are failing while running the cmake build (using it is outlined in DEVELOPERS.md) rather than the maven build. The cmake build creates a proton-j jar by itself for use in certain tests, a process which these changes break through introduction of a compile time dependency on bouncycastle that it doesn't accommodate because it didn't previously need to. Either the update needs to be made fully-reflective as before, or the cmake build updated to accommodate the new compilation dependency.

Some more general comments:

• The main module and tests are specifying difference versions of bouncycastle to use.
• If you include the JIRA title in the PR title, it will be updated by a bot upon PR open/comments/close.
• Please reference the JIRA in commit msg, i.e "PROTON-XYZ: msg".
• Please remove merge commits from PRs.

(Mentioning PROTON-1224 so it also gets updated)

[JemDay]

OK .. i'll take a look at setting up a cmake environment and cleaning the commits..

[JemDay]

Closing PR .. will recreate