Always include legacy client options in error output

[lbschanno]

The ClientOpts class does not always include the names of legacy options in its error output when a user provides legacy options to the Accumulo client.

Make the following changes:

• Break the legacy options in ClientOpts into individual properties that can be set by JCommander.
• Add ClientOpts.getPopulatedLegacyOptions() which will return a set of all user-provided legacy options.
• Update ClientOpts.validateArgs() to check for the presence of any legacy options, and include them in the error message.

Fixes #6501

I tested these changes on a running instance. Some examples:

~/src/accumulo-uno ⑂main* $ accumulo shell -u root -p secret
SLF4J(W): Class path contains multiple SLF4J providers.
SLF4J(W): Found provider [org.apache.logging.slf4j.SLF4JServiceProvider@1175e2db]
SLF4J(W): Found provider [ch.qos.logback.classic.spi.LogbackServiceProvider@36aa7bc2]
SLF4J(W): See https://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J(I): Actual provider is of type [org.apache.logging.slf4j.SLF4JServiceProvider@1175e2db]
Received options [-p]
Thread 'shell' died.
java.lang.IllegalArgumentException: The Client options -p have been dropped. Use accumulo-client.properties for any connection or token options. See '-c, --config-file' option.
	at org.apache.accumulo.core.cli.ClientOpts.validateArgs(ClientOpts.java:227)
	at org.apache.accumulo.core.cli.BaseKeywordExecutable.execute(BaseKeywordExecutable.java:51)
	at org.apache.accumulo.start.Main.lambda$execKeyword$1(Main.java:116)
	at java.base/java.lang.Thread.run(Thread.java:1583)

~/src/accumulo-uno ⑂main* $ accumulo shell -u root -p secret --debug
SLF4J(W): Class path contains multiple SLF4J providers.
SLF4J(W): Found provider [org.apache.logging.slf4j.SLF4JServiceProvider@1175e2db]
SLF4J(W): Found provider [ch.qos.logback.classic.spi.LogbackServiceProvider@36aa7bc2]
SLF4J(W): See https://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J(I): Actual provider is of type [org.apache.logging.slf4j.SLF4JServiceProvider@1175e2db]
Received options [-p, --debug]
Thread 'shell' died.
java.lang.IllegalArgumentException: The Client options -p --debug have been dropped. Use accumulo-client.properties for any connection or token options. See '-c, --config-file' option.
	at org.apache.accumulo.core.cli.ClientOpts.validateArgs(ClientOpts.java:227)
	at org.apache.accumulo.core.cli.BaseKeywordExecutable.execute(BaseKeywordExecutable.java:51)
	at org.apache.accumulo.start.Main.lambda$execKeyword$1(Main.java:116)
	at java.base/java.lang.Thread.run(Thread.java:1583)