Support parsing Doris SHOW RESOURCES syntax

[ccxxxyy]

for #31458

official document:

• https://doris.apache.org/docs/4.x/sql-manual/sql-statements/cluster-management/compute-management/SHOW-RESOURCES

Changes proposed in this pull request:

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[ccxxxyy]

• Regarding RESOURCES and RESOURCETYPE, Doris does not treat them as reserved keywords. Therefore, I have added them to identifierKeywordsUnambiguous in BaseRule.g4, so that they can be used in places where identifiers are expected.

• Added two assertions and test cases (SELECT resources FROM t_resources and SELECT resourcetype FROM t_resourcetype) in src/main/resources/case/dml/select.xml and src/main/resources/sql/supported/dml/select.xml as counterexamples. All assertion tests passed, verifying that RESOURCES and RESOURCETYPE can be successfully used as identifiers.

• All modifications made in DALStatement.g4, DorisKeyword.g4, and BaseRule.g4 have been marked with // DORIS ADDED BEGIN and // DORIS ADDED END to facilitate future maintenance