Add jwt auth token expire check and modify some messages when connecting Splunk

[Tatsuya-hasegawa]

Hello,

I have some additional things to SplunkDriver.

The biggest one is that JWT bear_token's expiration check was implemented by using pyjwt which is already in requirement.txt.
In addition, I put some distinguish messages for each auth method when connecting Splunk.
And then modify an error in Splunk QueryProvider doc.

Local code check has been succeeded as following.

 % git commit -m "add jwt auth token expire check and modify some messages when connecting Splunk"
Check Yaml...........................................(no files to check)Skipped
Check JSON...........................................(no files to check)Skipped
Trim Trailing Whitespace.................................................Passed
black....................................................................Passed
pylint...................................................................Passed
flake8...................................................................Passed
isort (python)...........................................................Passed
pydocstyle...............................................................Passed
check_reqs_all...........................................................Passed
[add_token_expire_check_to_splunk_driver a4627c6f] add jwt auth token expire check and modify some messages when connecting Splunk
 3 files changed, 110 insertions(+), 39 deletions(-)

The JWT expiration time is shown by this commit.

This is an expire message, in this case, I modified the current time to over the expiration date forcely in order to appear this message.

Thank you.
Best regards,

[Tatsuya-hasegawa]

Oops, I noticed pulled my folk repository's main instead of microsoft:main before this commit.
So This PR's Files Changes diff includes the previous PR #731 .
The correct diff to microsoft:main is only the area of "This branch has conflicts that must be resolved" below.

I'm sorry.
Kind regards,

[Tatsuya-hasegawa]

Got it, I have completely fixed.
This PR's Files Changes diff is correct now.
Best regards,

Thank you in advance for your eye, @ianhelle

[ianhelle]

Looks good but a couple of minor issues.

[Tatsuya-hasegawa]

@ianhelle

Thanks for your check and the advices.
I fixed them by this commit.

% git commit -m "small changes for exceptional messages"
Check Yaml...........................................(no files to check)Skipped
Check JSON...........................................(no files to check)Skipped
Trim Trailing Whitespace.................................................Passed
black....................................................................Passed
pylint...................................................................Passed
flake8...................................................................Passed
isort (python)...........................................................Passed
pydocstyle...............................................................Passed
check_reqs_all...........................................................Passed
[add_token_expire_check_to_splunk_driver eeb9df46] small changes for exceptional messages
 2 files changed, 8 insertions(+), 7 deletions(-)

Would you kindly check them again?
Best regards,

[Tatsuya-hasegawa]

Thanks for your approval and merge.

[ianhelle]

@Tatsuya-hasegawa - thank you, once again for the contribution. It's awesome to have someone actively working on the Splunk support!