[SHIRO-770] Remove base64 implementation, keep UTF-8 codec by default.

[bmarwell]

For v2.0.0, we probably do not want to maintain our own Base64 implementation.

Still, the shiro implementation defaulted to UTF-8 for decoding strings, which seems to be a sane default.

However, the CryptoException became unreachable from the Base64 class. As this is not cryptography anyway, I decided to replace it with the IllegalArgumentException thrown by java.util.Base64's methods.

[fpapon]

Build is broken because of jacip maven plugin for api incompatibility but it's normal as we move on 2.0.0 and we want to broke this.
I will deactivate this.

[bdemers]

Build is broken because of jacip maven plugin for api incompatibility but it's normal as we move on 2.0.0 and we want to broke this.
I will deactivate this.

+1, the config probably needs to change as a major version change in the pom should allow for breaking API changes.
But, for exactly that same reason, we don't need to be running japicmp right now anyway.

Once we get closer to a beta for date for 2.x, we can generate a japicmp report and list out the API changes.

[bdemers]

@bmhm great change! PRs that remove code are my favorite 😄

[fpapon]

retest this please

[fpapon]

@bmhm can you create a Jira for this issue?

[bmarwell]

@bmhm can you create a Jira for this issue?

SHIRO-770 - https://issues.apache.org/jira/browse/SHIRO-770

[fpapon]

LGTM